fix(zynqmp): resolve null pointer dereferencing

The upstream coverity tool has reported the null pointer dereferences
(NULL_RETURNS) warning.

The coverity warning,
Dereferencing a pointer that might be "NULL" "proc" when calling
"pm_client_suspend".

Fix the same by checking the NULL before processing further.

Change-Id: I33acead9250bab0ed24b94aa1c1bdc31e80de771
Signed-off-by: Ronak Jain <ronak.jain@amd.com>
diff --git a/plat/xilinx/zynqmp/pm_service/zynqmp_pm_api_sys.c b/plat/xilinx/zynqmp/pm_service/zynqmp_pm_api_sys.c
index 6b42055..3d546b3 100644
--- a/plat/xilinx/zynqmp/pm_service/zynqmp_pm_api_sys.c
+++ b/plat/xilinx/zynqmp/pm_service/zynqmp_pm_api_sys.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2013-2022, Arm Limited and Contributors. All rights reserved.
- * Copyright (c) 2022-2023, Advanced Micro Devices, Inc. All rights reserved.
+ * Copyright (c) 2022-2024, Advanced Micro Devices, Inc. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -272,6 +272,11 @@
 	uint32_t cpuid = plat_my_core_pos();
 	const struct pm_proc *proc = pm_get_proc(cpuid);
 
+	if (proc == NULL) {
+		WARN("Failed to get proc %d\n", cpuid);
+		return PM_RET_ERROR_INTERNAL;
+	}
+
 	/*
 	 * Do client specific suspend operations
 	 * (e.g. set powerdown request bit)