LED support was dropped from the BU images due to a lack
of proper abstraction for LED definitions between CC and
CC3D HW variants in the CopterControl board family.
Use the new LED abstraction to hide board revision details
from the BU image so it can once again flash some LEDs.
hardware revision it cannot know which pios_led_cfg_ structure to use.
Possibly this should be abstracted further into board_hw_defs to create
functions like board_init_led.
Also the BU should probably compare the hw_revision of the original and new
bootloader to make sure the user doesn't break their board.
Board specific HW configuration is now collected in a single .c
file for each board. This HW configuration is #include'd into
the FW, BL and BU builds for each board.
These new .c files are found in:
flight/board_hw_defs/<board_name>/board_hw_defs.c
Parts of this information were previously duplicated between
the BL and FW builds. This commit cleans up the duplication.
Using a #include on a .c file is a bit ugly but it allows us
to ensure that all of the symbols in the board_hw_defs.c file
are *ONLY* used in the PIOS_Board_Init() function for each
software build.
