As we are about to handle system registers quite differently between VHE
and non-VHE systems.  In preparation for that, we need to split some of
the handling functions between VHE and non-VHE functionality.

For now, we simply copy the non-VHE functions, but we do change the use
of static keys for VHE and non-VHE functionality now that we have
separate functions.
Reviewed-by: NAndrew Jones <drjones@redhat.com>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NChristoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>