plat/arm: Fix MISRA defects in SiP SVC handler

No functional changes.

Change-Id: I9b9f8d3dfde08d57706ad5450de6ff858a55ac01
Signed-off-by: Antonio Nino Diaz <antonio.ninodiaz@arm.com>
diff --git a/plat/arm/common/arm_sip_svc.c b/plat/arm/common/arm_sip_svc.c
index e450c6f..e482a89 100644
--- a/plat/arm/common/arm_sip_svc.c
+++ b/plat/arm/common/arm_sip_svc.c
@@ -58,7 +58,7 @@
 
 		/* Validate supplied entry point */
 		pc = (u_register_t) ((x1 << 32) | (uint32_t) x2);
-		if (arm_validate_ns_entrypoint(pc))
+		if (arm_validate_ns_entrypoint(pc) != 0)
 			SMC_RET1(handle, STATE_SW_E_PARAM);
 
 		/*