omxvideodec: fix OMX flags on header buffer

The header (SPS/PPS) buffer should have the CODECONFIG flag and not the
ENDOFFRAME one as it's not actually a frame.
7 jobs for codecconfig-master in 16 minutes and 28 seconds (queued for 2 seconds)
latest
Status Name Job ID Coverage
  Preparation
passed gst indent #448837

00:00:17

passed manifest #448836

00:00:41

 
  Build
passed build fedora x86_64 #448838

00:06:37

passed build nodebug fedora x86_64 #448839

00:05:55

passed build static fedora x86_64 #448840

00:11:19

passed build static nodebug fedora x86_64 #448841

00:11:30

 
  Integrate
passed documentation #448842

00:04:15