arm64: alternatives: use cpucap naming

arm64: alternatives: use cpucap naming

To more clearly align the various users of the cpucap enumeration, this patch
changes the alternative code to use the term `cpucap` in favour of `feature`.
The alternative_has_feature_{likely,unlikely}() functions are renamed to
alternative_has_cap_<likely,unlikely}() to more clearly align with the
cpus_have_{const_,}cap() helpers.

At the same time remove the stale comment referring to the "ARM64_CB
bit", which is evidently a typo for ARM64_CB_PATCH, which was removed in
commit:

  4c0bd995d73ed889 ("arm64: alternatives: have callbacks take a cap")

There should be no functional change as a result of this patch; this is
purely a renaming exercise.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230607164846.3967305-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>