arm64/cpufeature: Consistently use symbolic constants for min_field_value

A number of the cpufeatures use raw numbers for the minimum field values
specified rather than symbolic constants. In preparation for the use of
helper macros replace all these with the appropriate constants.

No change in the generated binary.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230303-arm64-cpufeature-helpers-v2-2-4c8f28a6f203@kernel.org


Signed-off-by: Will Deacon <will@kernel.org>