KVM: arm64: GICv2: Decouple GICH_HCR programming from LRs being loaded

KVM: arm64: GICv2: Decouple GICH_HCR programming from LRs being loaded

Not programming GICH_HCR while no LRs are populated is a bit
of an issue, as we otherwise don't see any maintenance interrupt
when the guest interacts with the LRs.

Decouple the two and always program the control register, even when
we don't have to touch the LRs.

This is very similar to what we are already doing for GICv3.

Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: Mark Brown <broonie@kernel.org>
Link: https://msgid.link/20251120172540.2267180-17-maz@kernel.org
Signed-off-by: Oliver Upton <oupton@kernel.org>