MA-17597-3 mfd: imx-audiomix: add license for module build

Add license to support module build.

Signed-off-by: Jindong <jindong.yue@nxp.com>
Reviewed-by: Daniel Baluta <daniel.baluta@nxp.com>

drivers/mfd/imx-audiomix.c

@@ -46,3 +46,4 @@ static struct platform_driver imx_audiomix_driver = {
 	},
 };
 module_platform_driver(imx_audiomix_driver);
+MODULE_LICENSE("GPL v2");