[media] cx231xx: fix undefined function cx231xx_g_chip_ident()

This patch:
http://git.linuxtv.org/media_tree.git/commit/b86d15440b683f8634c0cb26fc0861a5bc4913ac
is missing a chunk when compared to an older version:
https://patchwork.kernel.org/patch/2063281/
probably because of an unresolved merging conflict.
This causes the following error:
WARNING: "cx231xx_g_chip_ident" [/home/jena/media_build/v4l/cx231xx.ko] undefined!
Signed-off-by: NGianluca Gennari <gennarone@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/usb/cx231xx/cx231xx-video.c

@@ -1227,7 +1227,7 @@ int cx231xx_s_frequency(struct file *file, void *priv,
 	return rc;
 }
 
-int vidioc_g_chip_ident(struct file *file, void *fh,
+int cx231xx_g_chip_ident(struct file *file, void *fh,
 			struct v4l2_dbg_chip_ident *chip)
 {
 	chip->ident = V4L2_IDENT_NONE;