videodecoders: use default pad accept-caps handling

Avoids useless check of downstream caps when handling an
accept-caps query

Elements: daaladec, libde265dec, openjpegdec, rsvgdec, schrodec,
          webpdec, pnmdec, vmncdec, openexrdec
diff --git a/ext/openexr/gstopenexrdec.cpp b/ext/openexr/gstopenexrdec.cpp
index d2d1dff..a334b0a 100644
--- a/ext/openexr/gstopenexrdec.cpp
+++ b/ext/openexr/gstopenexrdec.cpp
@@ -151,6 +151,9 @@
   GstVideoDecoder *decoder = (GstVideoDecoder *) self;
 
   gst_video_decoder_set_packetized (decoder, FALSE);
+  gst_video_decoder_set_use_default_pad_acceptcaps (GST_VIDEO_DECODER_CAST
+      (self), TRUE);
+  GST_PAD_SET_ACCEPT_TEMPLATE (GST_VIDEO_DECODER_SINK_PAD (self));
 }
 
 static gboolean