fix(zynqmp): handle secure SGI at EL1 for OP-TEE

OP-TEE requires SGIs to be handled at S-EL1. The
Makefile was not properly setting the flag
GICV2_G0_FOR_EL3 to 0 when the SPD is OP-TEE.

Change-Id: I256afa37ddf4ad4a154c43d51807de670c3689bb
Signed-off-by: Shen Jiamin <shen_jiamin@comp.nus.edu.sg>

plat/xilinx/zynqmp/platform.mk

@@ -21,7 +21,7 @@ ENABLE_LTO := 1
 EL3_EXCEPTION_HANDLING := $(SDEI_SUPPORT)
 
 # pncd SPD requires secure SGI to be handled at EL1
-ifeq (${SPD}, $(filter ${SPD},pncd tspd))
+ifeq (${SPD}, $(filter ${SPD},pncd tspd opteed))
 ifeq (${ZYNQMP_WDT_RESTART},1)
 $(error "Error: ZYNQMP_WDT_RESTART and SPD=pncd are incompatible")
 endif