plat: imx8mn: correct the noc power down setting

The NOC power down is skipped by mistake before, so fix it.
Additionally, the OCRAM memory region protection is enabled
by ROM, but does NOT disable it. it should be disabled by
default. if there are requirments for RDC memory region
protection for OCRAM space, we can reconfigure it and enable
it again.
Signed-off-by: Jacky Bai <ping.bai@nxp.com>

plat/imx/imx8mn/gpc.c

@@ -683,8 +683,6 @@ static void imx_gpc_pm_domain_enable(uint32_t domain_id, uint32_t on)
 				;
 		}
 	} else {
-		return;
-
 		pu_domain_status &= ~(1 << domain_id);
 
 		if (domain_id == OTG1)

plat/imx/imx8mn/imx8mn_bl31_setup.c

@@ -203,6 +203,14 @@ void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
 	/* config the caam access permission */
 	imx8mn_caam_config();
 
+	/*
+	 * ROM enabled the RDC config for OCRAM space, just disable
+	 * it. it can be reconfigured based on the system requirement.
+	 */
+	mmio_write_32(IMX_RDC_BASE + 0x908, 0xff);
+	mmio_write_32(IMX_RDC_BASE + 0x918, 0xff);
+	mmio_write_32(IMX_RDC_BASE + 0x928, 0xff);
+
 #if DEBUG_CONSOLE
 	console_uart_register(IMX_BOOT_UART_BASE, IMX_BOOT_UART_CLK_IN_HZ,
 		IMX_CONSOLE_BAUDRATE, &console);