arm64: cpufeature: Account min_field_value when cheking secondaries for PAuth

In case, both boot_val and sec_val have value below min_field_value we
would wrongly report that address authentication is supported. It is
not a big issue because we enable address authentication based on boot
cpu (and check there is correct).

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220224124952.119612-2-vladimir.murzin@arm.com


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