arm64: add missing feature identification to align with ARMv8.9
Feature bit definitions in armreg.h have been updated to align with
ARMv8.9. This change implements those updates in identcpu.c.
Reviewed by: andrew
Sponsored by: Arm Ltd
Differential Revision: https://reviews.freebsd.org/D48816
Signed-off-by: Harry Moulton <harry.moulton@arm.com>