[media] v4l: s5p-tv: Fix section mismatch warning in mixer_video.c
The function __devinit mxr_probe() references
a function __devexit mxr_release_video().
Since mxr_release_video() is referenced outside the exit section, the following
compilation warning is generated which is fixed here:
WARNING: drivers/media/video/s5p-tv/s5p-mixer.o(.devinit.text+0x340):
Section mismatch in reference from the function mxr_probe() to the function
devexit.text:mxr_release_video()