Revert "cpu: add HPDS, LOR, PAN detection for arm64"

This reverts CL 704075.

Reason for revert: Based on golang/go#76386, it doesn't seem to work correctly.

Fixes golang/go#76386.

Change-Id: I51ccbc8715c25c0d061d56dfbf0e8158f1207018
Reviewed-on: https://go-review.googlesource.com/c/sys/+/724160
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Auto-Submit: Cherry Mui <cherryyz@google.com>