If there were LPIs being mapped behind our back (i.e., between .start() and
.stop()), we would put them at iter_unmark_lpis() without checking if they
were actually *marked*, which is obviously not good.

Switch to use the xa_for_each_marked() iterator to fix it.

Cc: stable@vger.kernel.org
Fixes: 85d3ccc8 ("KVM: arm64: vgic-debug: Use an xarray mark for debug iterator")
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240817101541.1664-1-yuzenghui@huawei.comSigned-off-by: Oliver Upton <oliver.upton@linux.dev>