plat: imx8mm: enable noc power down support

enable NOC power down in DSM mode.

Signed-off-by: Bai Ping <ping.bai@nxp.com>
(cherry picked from commit 4f9398bda8c43df6db3297fd8413bb5c4bac179e)
diff --git a/plat/imx/imx8mm/gpc.c b/plat/imx/imx8mm/gpc.c
index a2eabbb..c022402 100644
--- a/plat/imx/imx8mm/gpc.c
+++ b/plat/imx/imx8mm/gpc.c
@@ -547,9 +547,9 @@
 	mmio_write_32(IMX_GPC_BASE + MST_CPU_MAPPING, val);
 
 	/* noc can only be power down when all the pu domain is off */
-//	if (!pu_domain_status)
-//		/* enable noc power down */
-//		imx_noc_slot_config(true);
+	if (!pu_domain_status)
+		/* enable noc power down */
+		imx_noc_slot_config(true);
 	/*
 	 * gic redistributor context save must be called when
 	 * the GIC CPU interface is disabled and before distributor save.
@@ -572,9 +572,9 @@
 	mmio_write_32(IMX_GPC_BASE + MST_CPU_MAPPING, val);
 
 	/* noc can only be power down when all the pu domain is off */
-//	if (!pu_domain_status)
-//		/* disable noc power down */
-//		imx_noc_slot_config(false);
+	if (!pu_domain_status)
+		/* disable noc power down */
+		imx_noc_slot_config(false);
 
 	/* restore gic context */
 	plat_gic_restore(proc_num, &imx_gicv3_ctx);