[media] gspca: ov534/topro: use a define for the default framerate

When writing the change in commit dcc7fdbec5 ("[media] gspca:
ov534/topro: prevent a division by 0") I used magic numbers for the
default framerate to minimize the code footprint to make it easier to
backport the patch to the stable trees.

However it's better if the default framerate has its own define to avoid
risking using different values in different places, and for readability.

While at it also remove some trivial comments about the framerates which
don't add much to the code anymore.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/usb/gspca/ov534.c

@@ -51,6 +51,7 @@
 #define OV534_OP_READ_2		0xf9
 
 #define CTRL_TIMEOUT 500
+#define DEFAULT_FRAME_RATE 30
 
 MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
 MODULE_DESCRIPTION("GSPCA/OV534 USB Camera Driver");
@@ -1061,7 +1062,7 @@ static int sd_config(struct gspca_dev *gspca_dev,
 	cam->cam_mode = ov772x_mode;
 	cam->nmodes = ARRAY_SIZE(ov772x_mode);
 
-	sd->frame_rate = 30;
+	sd->frame_rate = DEFAULT_FRAME_RATE;
 
 	return 0;
 }
@@ -1492,10 +1493,8 @@ static void sd_set_streamparm(struct gspca_dev *gspca_dev,
 	struct sd *sd = (struct sd *) gspca_dev;
 
 	if (tpf->numerator == 0 || tpf->denominator == 0)
-		/* Set default framerate */
-		sd->frame_rate = 30;
+		sd->frame_rate = DEFAULT_FRAME_RATE;
 	else
-		/* Set requested framerate */
 		sd->frame_rate = tpf->denominator / tpf->numerator;
 
 	if (gspca_dev->streaming)