boards: faze: enable BUILD_OUTPUT_HEX

Since commit 3124c029
("cmake: flash/debug: refactor runner configuration"), BUILD_OUTPUT_HEX
must be selected to pass the .hex file to the runner. It is needed when
running the "west flash" command.

In addition the implicit CORTEX_M_SYSTICK option is removed.

Signed-off-by: Simon Guinot <simon.guinot@seagate.com>