arm64: Update the ID_AA64PFR0_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/D40895

(cherry picked from commit 0766dde9b5587d04c634eda1ab4666203d32a271)