[media] v4l: fix compiler warnings

[media] v4l: fix compiler warnings

media_build/v4l/adv7343.c: In function 'adv7343_setstd':
media_build/v4l/adv7343.c:133:6: warning: variable 'output_idx' set but not used [-Wunused-but-set-variable]
media_build/v4l/tvp5150.c: In function 'tvp5150_mbus_fmt':
media_build/v4l/tvp5150.c:833:14: warning: variable 'std' set but not used [-Wunused-but-set-variable]
media_build/v4l/tvp7002.c: In function 'tvp7002_query_dv_preset':
media_build/v4l/tvp7002.c:673:18: warning: variable 'device' set but not used [-Wunused-but-set-variable]
media_build/v4l/c-qcam.c: In function 'qc_capture':
media_build/v4l/c-qcam.c:381:33: warning: variable 'bitsperxfer' set but not used [-Wunused-but-set-variable]
media_build/v4l/pms.c: In function 'pms_s_std':
media_build/v4l/pms.c:738:6: warning: variable 'ret' set but not used [-Wunused-but-set-variable]
media_build/v4l/pms.c: In function 'init_mediavision':
media_build/v4l/pms.c:959:6: warning: variable 'id' set but not used [-Wunused-but-set-variable]
media_build/v4l/cx25821-alsa.c: In function 'cx25821_irq':
media_build/v4l/cx25821-alsa.c:294:6: warning: variable 'audint_count' set but not used [-Wunused-but-set-variable]
media_build/v4l/zr364xx.c: In function 'zr364xx_fillbuff':
media_build/v4l/zr364xx.c:510:25: warning: variable 'frm' set but not used [-Wunused-but-set-variable]
media_build/v4l/s2255drv.c: In function 's2255_fillbuff':
media_build/v4l/s2255drv.c:637:23: warning: variable 'frm' set but not used [-Wunused-but-set-variable]
media_build/v4l/s2255drv.c: In function 'vidioc_s_fmt_vid_cap':
media_build/v4l/s2255drv.c:990:6: warning: variable 'norm' set but not used [-Wunused-but-set-variable]
media_build/v4l/tm6000-stds.c: In function 'tm6000_set_audio_std':
media_build/v4l/tm6000-stds.c:341:10: warning: variable 'nicam_flag' set but not used [-Wunused-but-set-variable]
media_build/v4l/tm6000-video.c: In function 'get_next_buf':
media_build/v4l/tm6000-video.c:172:8: warning: variable 'outp' set but not used [-Wunused-but-set-variable]
media_build/v4l/tm6000-video.c: In function 'copy_streams':
media_build/v4l/tm6000-video.c:214:36: warning: variable 'c' set but not used [-Wunused-but-set-variable]
media_build/v4l/tm6000-input.c: In function 'tm6000_ir_urb_received':
media_build/v4l/tm6000-input.c:171:6: warning: variable 'rc' set but not used [-Wunused-but-set-variable]
media_build/v4l/usbvision-core.c: In function 'usbvision_decompress':
media_build/v4l/usbvision-core.c:604:23: warning: variable 'max_pos' set but not used [-Wunused-but-set-variable]
media_build/v4l/usbvision-core.c: In function 'usbvision_parse_compress':
media_build/v4l/usbvision-core.c:705:39: warning: variable 'rc' set but not used [-Wunused-but-set-variable]
media_build/v4l/usbvision-core.c:705:22: warning: variable 'bytes_per_pixel' set but not used [-Wunused-but-set-variable]
media_build/v4l/zoran_device.c: In function 'write_overlay_mask':
media_build/v4l/zoran_device.c:545:6: warning: variable 'reg' set but not used [-Wunused-but-set-variable]
media_build/v4l/go7007-v4l2.c: In function 'go7007_streamoff':
media_build/v4l/go7007-v4l2.c:79:6: warning: variable 'retval' set but not used [-Wunused-but-set-variable]

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>