[TF-A] Minor update to Platform ports requirements

Hi All / Platform owners,

There is a minor update to Platform ports requirements based on patches merged recently. https://trustedfirmware-a.readthedocs.io/en/latest/porting-guide.html#build-...

So please use correct ARM_ARCH_MAJOR and ARM_ARCH_MINOR from platform makefile or from build options to utilize the 'arch_features.mk' to enable all mandatory features by default. Enabling of optional features remain unchanged and based on availability and need can be enabled from platform makefile.

Some of platform port convert examples are as below: https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/23463/20/plat... https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/23670/21/plat...

-- Thanks, Govindraj.R & Manish Pandey