If BOARD is unspecified, simplelink platform's build system will generate an error instead of choosing a default. This is a) inconsistent with what we do for other platforms and b) problematic because making targets clean, distclean etc will fail.
Working Simplelink platform with the following Simplelink SDK's:
* CC13x0 SDK
* CC13x2 SDK
* CC26x2 SDK
Is also compatible with Code Composer Studio (XDCTools)
NB! This is by no means a future-proof implementation. However, it
should be a good starting point. Configuration of the LEDS_ARCH_*
defines in the leds-arch.c file is what determines what LEDs are
available of a given device/target. This information should be
sufficient from the Board file/device name, and can from there
hardcod what board+device combination a given LED should support.
