HID: roccat: Use kmemdup rather than duplicating its implementation

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-roccat-common.c b/drivers/hid/hid-roccat-common.c
index edf898d..f933221 100644
--- a/drivers/hid/hid-roccat-common.c
+++ b/drivers/hid/hid-roccat-common.c
@@ -48,12 +48,10 @@
 	char *buf;
 	int len;
 
-	buf = kmalloc(size, GFP_KERNEL);
+	buf = kmemdup(data, size, GFP_KERNEL);
 	if (buf == NULL)
 		return -ENOMEM;
 
-	memcpy(buf, data, size);
-
 	len = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
 			HID_REQ_SET_REPORT,
 			USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,