imx8mq: Add csu support

   Enable the CSU driver for i.MX8MQ platform with a default settings
 as an example.

Signed-off-by: Aymen Sghaier <aymen.sghaier@nxp.com>
(cherry picked from commit 15a5bfb1856a80ce89b0553259b519fac35fcf7a)

Conflicts:
	plat/imx/imx8mq/platform.mk
5 files changed