arm64: Handle width of a cpuid feature
arm64: Handle width of a cpuid feature

Introduce a helper to extract cpuid feature for any given
width.

Signed-off-by: Suzuki K. Poulose <25f0e69a3d23ed1d9a060214a9ff1a9504ba3f49@arm.com>
Tested-by: Dave Martin <35bec38e6df2fd311d8334693ecd653c3d2c10b1@arm.com>
Signed-off-by: Catalin Marinas <15ce75b290ebaf27c3f9fd73ab848685ed3d8261@arm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs