KVM: arm64: vgic-v3: Don't require IRQs be disabled for LPI xarray lock

KVM: arm64: vgic-v3: Don't require IRQs be disabled for LPI xarray lock

Now that releases of LPIs have been unnested from the ap_list_lock there
are no xarray writers that exist in a context where IRQs are already
disabled. As such we can relax the locking to the non-IRQ disabling
spinlock to guard the LPI xarray.

Note that there are still readers of the LPI xarray where IRQs are
disabled however the readers rely on RCU protection instead of the lock.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250905100531.282980-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>