Add logic so that STM32 Ethernet drivier can avoid interrupt level processing and, instead, execute on the work thread.

SYSLOG: Add an option to use the syslog'ing device as the system consolution.  This option enables a low-level, write-only console device at /dev/console (similar to the low-level UART console device).  From Pierre-noel Bouteville.

STM32 SPI:  The source clock for SPI 4,5, and 6 should be PCLK2, not PCLK1 (for F411, F427, and F429).  Per David Sidrane.

STM32: Add an IPv6 configuration for the STM32F4-Discovery board (witht he STM32-DISCO_BB base board).  Verify that the STM32 Ethernet driver works with IPv6.

Add IPv6 support to network driver skeleton and to SAMA5D4 Ethernet driver (which, unfortunately is still missing address filtering logi)

ICMPv6:  Add logic to behave like a router (if so configured):  NuttX will not send the router advertisement message in response to any router solicitation messages.

Networking:  Break out Ethernet definitions into a separate file; add IPv6 multicast addresses as common globals, Ethernet drivers need to filter link-local, all nodes Ethernet address

Re-arrange condition logic from the last change to avoid having STM32-specific conditional logic outside of the STM32 sandbox.

STM32:  Add driver for STM32L162XX AES peripheral. Signed-off-by: Juha Niskanen <juha.niskanen@haltian.com>

Also remove spaces before and after paretheses to conform to coding standard.

drivers/ramdisk.c and include/nuttx/fs/ramdisk.h:  Add logic to dispose of the drvier and RAM buffer when the RAM disk has been unlinked and all open references to the RAM disk have been closed.  Add new parameters to romdisk() to specify what should be done with the RAM/ROM buffer -- Should it be freed or not?  Changed all calls to ramdisk() to use these new parameters.

EFM32: Logic to unconditionally enable LE clocking. Even you don't use core clock LE as source for LFA or LFB, to read are write any register not clocked by HFPERCLK or HFCORECLK, HFCORECLKLE should be enabled.  From Pierre-noel Bouteville.

ARM assembly language memcpy.S was not returning a value in R0 it is required to do.  From David Sidrane

Tiva Ethernet:  Move place where interrupts are disabled.  It is probably not possible, but the logic looks like it could leave interrupts disabled