omx: Always hold port->port_lock before signalling port->port_cond when notifying about errors
omx: Always hold port->port_lock before signalling port->port_cond when notifying about errors

Otherwise a port might be in the critical section, has checked the error state
already but waits after port->port_cond is signalled, which will lead
to a deadlock.

GStreamer/gst-omx,01org/gst-omx,zuh/gst-omx-rpi,renesas-rcar/gst-omx,varunkumara/test-repo,tjormola/gst-omx,RidgeRun/gst-omx,varunkumara/test-repo,surround-io/gst-omx,01org/gst-omx,pliu6/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,pliu6/gst-omx,GStreamer/gst-omx,CapOM/gst-omx,CapOM/gst-omx,zuh/gst-omx-rpi,ismelykh/gst-omx-deinterlace,CapOM/gst-omx,leio/gst-omx,renesas-rcar/gst-omx,changzhix/gst-omx,freedesktop-unofficial-mirror/gstreamer__gst-omx,RidgeRun/gst-omx,renesas-devel/gst-omx,surround-io/gst-omx,varunkumara/test-repo,xuguangxin/gst-omx,renesas-devel/gst-omx,changzhix/gst-omx,leio/gst-omx,GStreamer/gst-omx,xuguangxin/gst-omx,tjormola/gst-omx,renesas-rcar/gst-omx,ismelykh/gst-omx-deinterlace