zynqmp: Enable U-Boot run in EL3

Enable Secure IOU setup to enable U-Boot to run in EL3 without
setting from ATF.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/cpu/armv8/zynqmp/Kconfig b/arch/arm/cpu/armv8/zynqmp/Kconfig
index c8fcfb6..5f79740 100644
--- a/arch/arm/cpu/armv8/zynqmp/Kconfig
+++ b/arch/arm/cpu/armv8/zynqmp/Kconfig
@@ -20,4 +20,8 @@
 config SYS_CONFIG_NAME
 	default "xilinx_zynqmp_ep" if TARGET_ZYNQMP_EP
 
+config SECURE_IOU
+	bool "Configure ZynqMP secure IOU"
+	default n
+
 endif