arm64: Update the ID_AA64PFR1_EL1 fields

While here move to decimal for the _op and _CR definitions to be used
by a future macro to define the register when the assembler doesn't
know about it.

Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D40896

(cherry picked from commit 8c111e5b375897bc298b8cdb3095f3c0e29c2307)