can: gs_usb: fix memory leak in gs_cmd_reset()

This patch adds the missing kfree() in gs_cmd_reset() to free the
memory that is not used anymore after usb_control_msg().

Cc: linux-stable <stable@vger.kernel.org>
Cc: Maximilian Schneider <max@schneidersoft.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

drivers/net/can/usb/gs_usb.c

@@ -265,6 +265,8 @@ static int gs_cmd_reset(struct gs_usb *gsusb, struct gs_can *gsdev)
 			     sizeof(*dm),
 			     1000);
 
+	kfree(dm);
+
 	return rc;
 }