feat(imx8m): enable the csu init on imx8m

Enable the CSU init on i.MX8M SoC family. The 'csu_cfg' array
is just a placeholder for now as example with limited config listed.
In real use case,user can add the CSU config as needed based on system design.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: I1f7999efa346f18f6625ed8c478d088ed75f7833
diff --git a/plat/imx/imx8m/imx8mn/platform.mk b/plat/imx/imx8m/imx8mn/platform.mk
index 2c746fe..183b08c 100644
--- a/plat/imx/imx8m/imx8mn/platform.mk
+++ b/plat/imx/imx8m/imx8mn/platform.mk
@@ -23,6 +23,7 @@
 				plat/imx/imx8m/imx_aipstz.c			\
 				plat/imx/imx8m/imx_rdc.c			\
 				plat/imx/imx8m/imx8m_caam.c			\
+				plat/imx/imx8m/imx8m_csu.c			\
 				plat/imx/imx8m/imx8m_psci_common.c		\
 				plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c	\
 				plat/imx/imx8m/imx8mn/imx8mn_psci.c		\