[PATCH] mailbox: mediatek: add module license

The missing license tag in the new driver causes a compile-time warning,
and may result in the module being unusable if it calls EXPORT_SYMBOL_GPL()
functions:

WARNING: modpost: missing MODULE_LICENSE() in drivers/mailbox/mtk-cmdq-mailbox.o

Fixes: 623a6143a845 ("mailbox: mediatek: Add Mediatek CMDQ driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/mailbox/mtk-cmdq-mailbox.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mailbox/mtk-cmdq-mailbox.c b/drivers/mailbox/mtk-cmdq-mailbox.c
index 6f92c5ee12f7..aec46d5d3506 100644
--- a/drivers/mailbox/mtk-cmdq-mailbox.c
+++ b/drivers/mailbox/mtk-cmdq-mailbox.c

@@ -567,3 +567,5 @@ static void __exit cmdq_drv_exit(void)
 
 subsys_initcall(cmdq_drv_init);
 module_exit(cmdq_drv_exit);
+
+MODULE_LICENSE("GPL v2");