vaapidecode: decide allocation doesn't update srccaps
vaapidecode: decide allocation doesn't update srccaps

The received caps query will bring the already negotiated caps, so they are
not expected to change.

This patch removes this verification which is dead code path.

Signed-off-by: Víctor Manuel Jáquez Leal <victorx.jaquez@intel.com>

https://bugzilla.gnome.org/show_bug.cgi?id=756686

CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,CapOM/gstreamer-vaapi,GStreamer/gstreamer-vaapi,CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,ceyusa/gstreamer-vaapi,GStreamer/gstreamer-vaapi,ceyusa/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi