fix(plat/xilinx/versal): resolve misra R14.4

MISRA Violation: MISRA-C:2012 R.14.4
- The controlling expression of an if statement and the controlling
  expression of an iteration-statement shall have essentially Boolean type.

Signed-off-by: Abhyuday Godhasara <abhyuday.godhasara@xilinx.com>
Change-Id: I8cf821a42015858200cc0c514600012c8f61061f
diff --git a/plat/xilinx/versal/plat_psci.c b/plat/xilinx/versal/plat_psci.c
index 30742f7..eb05e58 100644
--- a/plat/xilinx/versal/plat_psci.c
+++ b/plat/xilinx/versal/plat_psci.c
@@ -205,7 +205,7 @@
 	}
 
 	/* We expect the 'state id' to be zero */
-	if (psci_get_pstate_id(power_state)) {
+	if (psci_get_pstate_id(power_state) != 0U) {
 		return PSCI_E_INVALID_PARAMS;
 	}