KVM: arm64: Promote guest ownership for DBGxVR/DBGxCR reads

Only yielding control of the debug registers for writes is a bit silly,
unless of course you're a fan of pointless traps. Give control of the
debug registers to the guest upon the first access, regardless of
direction.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20241219224116.3941496-20-oliver.upton@linux.dev


Signed-off-by: Marc Zyngier <maz@kernel.org>