V4L/DVB: drivers/media/video/gspca: Use kmemdup

Use kmemdup when some other buffer is immediately copied into the
allocated region.

A simplified version of the semantic patch that makes this change is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression from,to,size,flag;
statement S;
@@

-  to = \(kmalloc\|kzalloc\)(size,flag);
+  to = kmemdup(from,size,flag);
   if (to==NULL || ...) S
-  memcpy(to, from, size);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/gspca/t613.c

@@ -572,12 +572,11 @@ static void reg_w_buf(struct gspca_dev *gspca_dev,
 	} else {
 		u8 *tmpbuf;
 
-		tmpbuf = kmalloc(len, GFP_KERNEL);
+		tmpbuf = kmemdup(buffer, len, GFP_KERNEL);
 		if (!tmpbuf) {
 			err("Out of memory");
 			return;
 		}
-		memcpy(tmpbuf, buffer, len);
 		usb_control_msg(gspca_dev->dev,
 				usb_sndctrlpipe(gspca_dev->dev, 0),
 				0,