Both variables were used (with the same value) interchangeably
throughout CMake files and per the discussion in GH issue,
ZEPHYR_BASE is preferred.
Also add a comment with explanation of one vs. the other.
Tested by building hello_world for several boards ensuring no errors.
Fixes#7173.
Signed-off-by: Alex Tereschenko <alext.mkrs@gmail.com>
Support the ST STM32F0DISCOVERY board with STM32F051R8T6 SoC
Tested with:
- `samples/basic/blinky`
- `samples/basic/button`
Includes flash config in `stm32f0_disco.rst` for use with mcuboot
Signed-off-by: Nathan Tsoi <nathan@vertile.com>