qtmux: don't limit max video resolution to 4096x4096
qtmux: don't limit max video resolution to 4096x4096

MAX isn't entirely correct as upper limit either,
it should really be MAXUINT32, but it's unlikely
to be a problem in the near future.

https://bugzilla.gnome.org/show_bug.cgi?id=740407

wkatsak/gst-plugins-good,ndufresne/gst-plugins-good,jpakkane/gstreamer-plugins-good,jpakkane/gstreamer-plugins-good,vatavuserban/gst-plugins-good,jpakkane/gstreamer-plugins-good,wkatsak/gst-plugins-good,vatavuserban/gst-plugins-good,ndufresne/gst-plugins-good,ndufresne/gst-plugins-good,jpakkane/gstreamer-plugins-good,wkatsak/gst-plugins-good,wkatsak/gst-plugins-good,vatavuserban/gst-plugins-good,ndufresne/gst-plugins-good,vatavuserban/gst-plugins-good