Spirit Network Device:  Fix a deadlock.  Also several other design improvements to eliminate corner cases.

Fix for stm32f746g-disco board for button support with interrupt. This change is tested with buttons app example and it is working with interrupts (signals). I tried the test with polling but at this point it doesn't work.

b-l475e-iot91a:  Add apps/examples/nettest and eamples/udp to Spirit1 configuration.  Add telnet support.  fix driver statistics configuration.

lc823450 support

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

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

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

Spirit: Network driver needs to setup IP address based on configured node address.  If no node address is provided, then it will use a default.  Also upate a README.

Spirit:  Add more debug output.  Make sure device is in READY state after reset and before changing to STANDBY.

NX PR

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

stm32f746g-disco:  Make the initialization logic identical to the standard way that is done for all other board.

STM32F7:  Fix for coding standard violations that came in with cd3ca114 -- missed a file last time

STM32F7:  Fix for coding standard violations that came in with cd3ca114

IoT Board/Spirit:  Fix a few issues that interfered with testing.  Move console to the VCOM port (USART) for all configurations.  Rename the spirit-mac configuration to spirit-6lowpan.  Add lots of debug output the spirit network driver.

Bug fixes for STM32F769

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

STM32_RCC_DCKCFGR2 has nothing to do with PLLI2S; PLLI2S is not dependent on LTDC, instead on SAICLK1/2 generated from PLLI2S