drm/panfrost: Put mapping instead of shmem obj on panfrost_mmu_map_fault_addr() error

When panfrost_mmu_map_fault_addr() fails, the BO's mapping should be
unreferenced and not the shmem object which backs the mapping.

Cc: stable@vger.kernel.org
Fixes: bdefca2d ("drm/panfrost: Add the panfrost_gem_mapping concept")
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220630200601.1884120-2-dmitry.osipenko@collabora.com

drivers/gpu/drm/panfrost/panfrost_mmu.c

@@ -518,7 +518,7 @@ static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
 err_pages:
 	drm_gem_shmem_put_pages(&bo->base);
 err_bo:
-	drm_gem_object_put(&bo->base.base);
+	panfrost_gem_mapping_put(bomapping);
 	return ret;
 }