fix(zynqmp): check return status of pm_get_api_version

MISRA Violation: MISRA C-2012 Rule 17.7
- Check the return status of function pm_get_api_version
and return error in case of failure.

Signed-off-by: Naman Patel <naman.patel@amd.com>
Change-Id: I69fb000c04f22996da7965a09a1797c7bfaad252

plat/xilinx/zynqmp/pm_service/pm_svc_main.c

@@ -207,10 +207,16 @@ err:
  */
 int32_t pm_setup(void)
 {
+	enum pm_ret_status err;
 
 	pm_ipi_init(primary_proc);
 
-	pm_get_api_version(&pm_ctx.api_version);
+	err = pm_get_api_version(&pm_ctx.api_version);
+	if (err != PM_RET_SUCCESS) {
+		ERROR("BL31: Failed to read Platform Management API version. "
+		      "Return: %d\n", err);
+		return -EINVAL;
+	}
 	if (pm_ctx.api_version < PM_VERSION) {
 		ERROR("BL31: Platform Management API version error. Expected: "
 		      "v%d.%d - Found: v%d.%d\n", PM_VERSION_MAJOR,