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>
Add configuration, pinmux, dts and documentation for the STM32L476G
Discovery board based on the STM32L476VG SoC.
Signed-off-by: Arthur SFEZ <arthur.sfez@gmail.com>