soc: imx: imx8m-blk-ctrl: Add MODULE_LICENSE

Add MODULE_LICENSE to support building as a module.

Signed-off-by: Jindong Yue <jindong.yue@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

Author: JDYue

drivers/soc/imx/imx8m-blk-ctrl.c

@@ -895,3 +895,4 @@ static struct platform_driver imx8m_blk_ctrl_driver = {
 	},
 };
 module_platform_driver(imx8m_blk_ctrl_driver);
+MODULE_LICENSE("GPL");