mt76: Add missing include of linux/module.h

MODULE_FIRMWARE() is used in usb_mcu.c and provided by linux/module.h,
but this header file is not directly included. This causes problems in
backports with some kernel versions.

Add the missing include.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt76x0/usb_mcu.c

@@ -15,6 +15,7 @@
  */
 #include <linux/kernel.h>
 #include <linux/firmware.h>
+#include <linux/module.h>
 
 #include "mt76x0.h"
 #include "mcu.h"