V4L/DVB (11953): videobuf-dma-sg: return -ENOMEM if vmalloc fails

it is better return -ENOMEM than -EIO
Signed-off-by: Figo.zhang <figo1802@gmail.com>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/videobuf-dma-sg.c

@@ -252,7 +252,7 @@ int videobuf_dma_map(struct videobuf_queue* q, struct videobuf_dmabuf *dma)
 			vfree(dma->sglist);
 			dma->sglist = NULL;
 			dma->sglen = 0;
-			return -EIO;
+			return -ENOMEM;
 		}
 	}
 	return 0;