arm64: Add hypervisor safe helper for checking constant capabilities

arm64: Add hypervisor safe helper for checking constant capabilities

The hypervisor may not have full access to the kernel data structures
and hence cannot safely use cpus_have_cap() helper for checking the
system capability. Add a safe helper for hypervisors to check a constant
system capability, which *doesn't* fall back to checking the bitmap
maintained by the kernel. With this, make the cpus_have_cap() only
check the bitmask and force constant cap checks to use the new API
for quicker checks.

Cc: Robert Ritcher <[email protected]>
Cc: Tirumalesh Chalamarla <[email protected]>
Signed-off-by: Suzuki K Poulose <[email protected]>
Reviewed-by: Will Deacon <[email protected]>
Reviewed-by: Marc Zyngier <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>