drm/panthor: Fix a couple -ENOMEM error codes

These error paths forgot to set the error code to -ENOMEM.

Fixes: 647810e ("drm/panthor: Add the MMU/VM logical block")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/cf5bbba5-427e-4940-b91e-925f9fa71f8d@moroto.mountain

Author: Dan Carpenter

drivers/gpu/drm/panthor/panthor_mmu.c

@@ -1264,8 +1264,10 @@ static int panthor_vm_prepare_map_op_ctx(struct panthor_vm_op_ctx *op_ctx,
 	op_ctx->rsvd_page_tables.pages = kcalloc(pt_count,
 						 sizeof(*op_ctx->rsvd_page_tables.pages),
 						 GFP_KERNEL);
-	if (!op_ctx->rsvd_page_tables.pages)
+	if (!op_ctx->rsvd_page_tables.pages) {
+		ret = -ENOMEM;
 		goto err_cleanup;
+	}
 
 	ret = kmem_cache_alloc_bulk(pt_cache, GFP_KERNEL, pt_count,
 				    op_ctx->rsvd_page_tables.pages);
@@ -1318,8 +1320,10 @@ static int panthor_vm_prepare_unmap_op_ctx(struct panthor_vm_op_ctx *op_ctx,
 		op_ctx->rsvd_page_tables.pages = kcalloc(pt_count,
 							 sizeof(*op_ctx->rsvd_page_tables.pages),
 							 GFP_KERNEL);
-		if (!op_ctx->rsvd_page_tables.pages)
+		if (!op_ctx->rsvd_page_tables.pages) {
+			ret = -ENOMEM;
 			goto err_cleanup;
+		}
 
 		ret = kmem_cache_alloc_bulk(pt_cache, GFP_KERNEL, pt_count,
 					    op_ctx->rsvd_page_tables.pages);