refactor(build): refactor mandatory options

Currently we enable all mandatory options for a current MAJOR.MINOR
number without considering architecturally to what version the current
arch should be compliant with.

For example Arch v9 should be compliant with 8.5 and shouldn't
consider being compliant with 8.9, so refactor FEAT_* handling to
ensure we capture and handle compliance correctly.

So refactor to use a list and add FEAT_* which are only compliant
with a given arch rather than relying on all the FEAT_* from previous
should be enabled for given arch version.

Change-Id: I8b0dd076c168a647de43b8618fbbe607412f7cab
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
2 files changed