drm/etnaviv: add missing MMU context put when reaping MMU mapping

When we forcefully evict a mapping from the the address space and thus the
MMU context, the MMU context is leaked, as the mapping no longer points to
it, so it doesn't get freed when the GEM object is destroyed. Add the
mssing context put to fix the leak.

Cc: stable@vger.kernel.org # 5.4
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Tested-by: NMichael Walle <michael@walle.cc>
Tested-by: NMarek Vasut <marex@denx.de>
Reviewed-by: NChristian Gmeiner <christian.gmeiner@gmail.com>

drivers/gpu/drm/etnaviv/etnaviv_mmu.c

@@ -199,6 +199,7 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu_context *context,
 		 */
 		list_for_each_entry_safe(m, n, &list, scan_node) {
 			etnaviv_iommu_remove_mapping(context, m);
+			etnaviv_iommu_context_put(m->context);
 			m->context = NULL;
 			list_del_init(&m->mmu_node);
 			list_del_init(&m->scan_node);