docs: move common build option from Arm-specific to common file

Moved common build options from Arm-specific file to common build
file.

Change-Id: If74b6223972ae3a6c11d9f9d2fbd8d2ee008b6e5
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
2 files changed