imx: imx8qx: add system reset support

Add system reset support for i.MX8QX,
when Linux kernel issues "reboot" command,
TF-A will send command to inform system
controller to reset whole board according
to board design, tested on i.MX8QX MEK board.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
diff --git a/plat/imx/imx8qx/imx8qx_psci.c b/plat/imx/imx8qx/imx8qx_psci.c
index 1e8f7fa..80f747b 100644
--- a/plat/imx/imx8qx/imx8qx_psci.c
+++ b/plat/imx/imx8qx/imx8qx_psci.c
@@ -65,6 +65,7 @@
 	.pwr_domain_on_finish = imx_pwr_domain_on_finish,
 	.validate_ns_entrypoint = imx_validate_ns_entrypoint,
 	.system_off = imx_system_off,
+	.system_reset = imx_system_reset,
 };
 
 int plat_setup_psci_ops(uintptr_t sec_entrypoint,