V4L/DVB: drivers: usbvideo: remove custom implementation of hex_to_bin()

Signed-off-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/usbvideo/usbvideo.c

@@ -282,19 +282,15 @@ static void usbvideo_OverlayChar(struct uvd *uvd, struct usbvideo_frame *frame,
 	};
 	unsigned short digit;
 	int ix, iy;
+	int value;
 
 	if ((uvd == NULL) || (frame == NULL))
 		return;
 
-	if (ch >= '0' && ch <= '9')
-		ch -= '0';
-	else if (ch >= 'A' && ch <= 'F')
-		ch = 10 + (ch - 'A');
-	else if (ch >= 'a' && ch <= 'f')
-		ch = 10 + (ch - 'a');
-	else
+	value = hex_to_bin(ch);
+	if (value < 0)
 		return;
-	digit = digits[ch];
+	digit = digits[value];
 
 	for (iy=0; iy < 5; iy++) {
 		for (ix=0; ix < 3; ix++) {