[media] ivtv: get rid of warning: no previous prototype

drivers/media/pci/ivtv/ivtv-alsa-main.c:208:5: warning: no previous prototype for 'ivtv_alsa_load' [-Wmissing-prototypes]
drivers/media/pci/ivtv/ivtv-alsa-pcm.c:325:5: warning: no previous prototype for 'snd_ivtv_pcm_create' [-Wmissing-prototypes]
drivers/media/pci/ivtv/ivtv-alsa-pcm.c:72:6: warning: no previous prototype for 'ivtv_alsa_announce_pcm_data' [-Wmissing-prototypes]
drivers/media/pci/ivtv/ivtv-firmware.c:279:5: warning: no previous prototype for 'ivtv_firmware_restart' [-Wmissing-prototypes]
drivers/media/pci/ivtv/ivtv-ioctl.c:1171:5: warning: no previous prototype for 'ivtv_s_std' [-Wmissing-prototypes]

Cc: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/pci/ivtv/ivtv-ioctl.c b/drivers/media/pci/ivtv/ivtv-ioctl.c
index 949ae23..31a69eb 100644
--- a/drivers/media/pci/ivtv/ivtv-ioctl.c
+++ b/drivers/media/pci/ivtv/ivtv-ioctl.c
@@ -1168,7 +1168,7 @@
 	}
 }
 
-int ivtv_s_std(struct file *file, void *fh, v4l2_std_id *std)
+static int ivtv_s_std(struct file *file, void *fh, v4l2_std_id *std)
 {
 	struct ivtv *itv = fh2id(fh)->itv;