internal/cpu: fix and cleanup ARM64 cpu feature fields and options
Remove all cpu features from the ARM64 struct that are not initialized
to reduce cache lines used and to avoid those features being
accidentially used without actual detection if they are present.
Add missing option to mask the CPUID feature.
Change-Id: I94bf90c0655de1af2218ac72117ac6c52adfc289
Reviewed-on: https://go-review.googlesource.com/c/go/+/267658
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Trust: Martin Möhrmann <moehrmann@google.com>