Revert "FROMLIST: KVM: arm64: pkvm: Use the mm_ops indirection for cache maintenance"

This reverts commit 9ad5e201.

The corresponding patch has been queued in the kvmarm tree as a fix for
5.17, so revert our FROMLIST version in preparation for pulling in the
upstream queue instead.

Bug: 209777660
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I7f65941b2b13125c6c6397590abbc3e18cb54496