KVM: arm64: Convert to the gfn-based MMU notifier callbacks

KVM: arm64: Convert to the gfn-based MMU notifier callbacks

Move arm64 to the gfn-base MMU notifier APIs, which do the hva->gfn
lookup in common code.

No meaningful functional change intended, though the exact order of
operations is slightly different since the memslot lookups occur before
calling into arch code.

Reviewed-by: Marc Zyngier <[email protected]>
Tested-by: Marc Zyngier <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <20210402005658.3024832[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>