toolchain: Ensure that Kconfig endianness matches the compiler's
toolchain: Ensure that Kconfig endianness matches the compiler's

In preparation for using CONFIG_(BIG|LITTLE)_ENDIAN exclusively for
endianness-based conditional compilation in the tree, ensure that the
Kconfig CONFIG_(BIG|LITTLE)_ENDIAN options match the compiler's
__BYTE_ORDER__ macro.

Signed-off-by: Carles Cufi <853081dc8dca4fe6a7e3c984752718b5db36e060@nordicsemi.no>

zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr