net: usb: ch9200: use kmemdup

Use kmemdup when some other buffer is immediately copied into allocated
region. It replaces call to allocation followed by memcpy, by a single
call to kmemdup.
Signed-off-by: Muhammad Falak R Wani <falakreyaz@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/ch9200.c

@@ -155,12 +155,11 @@ static int control_write(struct usbnet *dev, unsigned char request,
 		   index, size);
 
 	if (data) {
-		buf = kmalloc(size, GFP_KERNEL);
+		buf = kmemdup(data, size, GFP_KERNEL);
 		if (!buf) {
 			err = -ENOMEM;
 			goto err_out;
 		}
-		memcpy(buf, data, size);
 	}
 
 	err = usb_control_msg(dev->udev,