[GST1.14] Fix imxcompositor for GST1.14

- Need copy videoinfo to vagg->info

as in gst1.14 vdieoaggregator will check format info
need update vagg->info before negoiate.

Signed-off-by: Lyon Wang <lyon.wang@nxp.com>
diff --git a/plugins/compositor/gstimxcompositor.c b/plugins/compositor/gstimxcompositor.c
index 0c490b3..6147b6f 100755
--- a/plugins/compositor/gstimxcompositor.c
+++ b/plugins/compositor/gstimxcompositor.c
@@ -1036,6 +1036,8 @@
         1, G_MAXINT32, G_MAXINT32, 1, NULL);
   }
 
+  vagg->info = info;
+
   return ret;
 }