drivers/wiresless/ieee80211:  Correct some initialization problems with BCM43362 chip.  Adds BCM43428 support.  arch/arm/src: Add support for SDIO card to SDIO driver.

Squashed commit of the following:

Author: Gregory Nutt <gnutt@nuttx.org>
    include/nuttx/wireless/ieee80211:  Cosmetic, coding standard changes from review of last merge.
    drivers/wireless/ieee80211:  Cosmetic, coding standard changes from review of last merge.
    configs/photon:  Cosmetic, coding standard changes from review of last merge.
    arch/arm/src/stm32:  SDIO changes from last review:  Fix a few long lines and other coding standard issues; Make additions for SDIO card support dependent on a configuration option.

Author: hhuysqt <hyq9606@126.com>
    Return IEEE 802.11 MAC address just as ethernet does
    Modifyed bcmf_board_setup_oob_irq declaration
    Modified OOB ISR function types
    Add some logic according to WICED SDK
    Bug fixed: data_offset counts in 4-bytes
    Add BCM43438 logic for future developement
    Add tips on using telnet
    Use SDIO in-band interrupt instead of OOB interrupt, because Photon seems to unconnect the OOB interrupt line...
    add SDIO in-band interrupt logic

arch/arm/src/imxrt:  Minor reparitioning to account for the fact that the GPIO5 base address is not contiguous with the GPIO1-4 base addresses.

include/nuttx/wireless:  Add a setbaud() method to the HCI UART lower half interface that can be used to change the default BAUD selection.  arch/arm/src/stm32:  Implement the setbaud() method for the STM32 HCI UART.

net/udp:  Minor update from review of 091e3f73.  In connect(), AF_UNSPEC is used to disconnect UDP socket.  However, initial commit lacked logic to mark the socket as disconnected.

net/udp:  Fix several issues using connected UDP sockets:  sendto() should not accept and address.  Normally send() should be used instead.  recvfrom() is no longer necessary.  recvfrom() and poll() should not reset to accept any addresses but should, instead, only accept inputs and events from the connected remore peer.  On of these issues was noted by 李桂丁 <liguiding@pinecone.net>.  Changes were made as summarized here: http://www.masterraghu.com/subjects/np/introduction/unix_network_programming_v1.3/ch08lev1sec11.html

tools/configure.sh:  Fix last commit.  If gmake is not present, then 'which gmake' spews a lot of annoying error messages when configuring.  Best to pipe stderr to /dev/null so that we are blessedly unaware of the failures.

Add clang support to stm32f746g-disco board

Approved-by: Gregory Nutt <gnutt@nuttx.org>

drivers/1wire: add PM hooks and unlink support to sht21 sensor (allowing hot-swappable I2C bus from 1-wire converter)

* drivers/1wire: add PM hook to 1wire bus

* drivers/1wire/ds28e17.c: i2c instance must be zeroed

* drivers/sht21: add unlink support

    Unlike most other unlink implementations in NuttX drivers, this one
    does not allow any I2C operations after unlink, making it possible to
    deallocate the I2C bus.

Approved-by: Gregory Nutt <gnutt@nuttx.org>

configs/stm32f4discovery/hciuart:  Disable MMC/SD support.  That made it difficult to re-use the configuration without the base board.  MMC/SD support is not needed in that configuration anyway.

arch/arm/sc/lpc16xx:  Extends commit 456a258c:  Freeing endpoints should be set the same allocations as when endpoint was allocated.

configs:  Review all implementations of board_lcd_initialize().  The NuttX convention is that all internal functions that return errors as an 'int' must return a negated errno value on failure and a non-negative value on success.  Most were right but eight of them had cloned logic that returns 1 on success and zero on failure... both of which are interpreted as success by the caller since they are non-negative.

include/nuttx/wireless:  Add support for the rest of the IOCTL options needed to support apps/wireless/bluetooth/btsak.  This is only the IOCTL command definitions.  The IOCTL command implementation is still missing.

arch/arm/src/nrf52:  Add watchdog timer drivers.  Includes significant updates from Alan Carvalho de Assis <acassis@gmail.com>

drivers/net: Add TAP (network bridge) mode to tun.c

In previous implementation, TAP mode did not handle a packet
correctly. Also, the driver did not set the link layer type and
could not assign the interface name. This PR changes fix such
issues and supports TAP mode correctly.

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>

Approved-by: Gregory Nutt <gnutt@nuttx.org>