sgidec: add CODEC_CAP_DR1

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavcodec/sgidec.c

@@ -266,5 +266,6 @@ AVCodec ff_sgi_decoder = {
     .init           = sgi_init,
     .close          = sgi_end,
     .decode         = decode_frame,
+    .capabilities   = CODEC_CAP_DR1,
     .long_name      = NULL_IF_CONFIG_SMALL("SGI image"),
 };