chore(xilinx): follow kernel doc format for functional documentation

For TF-A, there is no format specified for functional documentation.
For AMD-Xilinx platforms, following kernel-doc format for the functional
documentation to make sure AMD-xilinx documentation is align with
actual code.

For example use kernel-doc from linux to call:
<linux>/scripts/kernel-doc -man -v 1 >/dev/null file...

Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
Change-Id: Idcc9def408b6c8da35b36f67ef82fc00890e998c
diff --git a/plat/xilinx/versal/plat_psci.c b/plat/xilinx/versal/plat_psci.c
index b901e3d..1bc30f1 100644
--- a/plat/xilinx/versal/plat_psci.c
+++ b/plat/xilinx/versal/plat_psci.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2018-2021, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2022-2023, Advanced Micro Devices, Inc. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -44,9 +45,9 @@
 
 /**
  * versal_pwr_domain_suspend() - This function sends request to PMC to suspend
- * core.
+ *                               core.
+ * @target_state: Targated state.
  *
- * @target_state	Targated state
  */
 static void versal_pwr_domain_suspend(const psci_power_state_t *target_state)
 {
@@ -81,9 +82,9 @@
 
 /**
  * versal_pwr_domain_suspend_finish() - This function performs actions to finish
- * suspend procedure.
+ *                                      suspend procedure.
+ * @target_state: Targated state.
  *
- * @target_state	Targated state
  */
 static void versal_pwr_domain_suspend_finish(
 					const psci_power_state_t *target_state)
@@ -120,8 +121,9 @@
 }
 
 /**
- * versal_system_off() - This function sends the system off request
- * to firmware.  This function does not return.
+ * versal_system_off() - This function sends the system off request to firmware.
+ *                       This function does not return.
+ *
  */
 static void __dead2 versal_system_off(void)
 {
@@ -135,8 +137,10 @@
 }
 
 /**
- * versal_system_reset() - This function sends the reset request
- * to firmware for the system to reset.  This function does not return.
+ * versal_system_reset() - This function sends the reset request to firmware
+ *                         for the system to reset.  This function does not
+ *			   return.
+ *
  */
 static void __dead2 versal_system_reset(void)
 {
@@ -150,9 +154,9 @@
 }
 
 /**
- * versal_pwr_domain_off() - This function performs actions to turn off core
+ * versal_pwr_domain_off() - This function performs actions to turn off core.
+ * @target_state: Targated state.
  *
- * @target_state	Targated state
  */
 static void versal_pwr_domain_off(const psci_power_state_t *target_state)
 {
@@ -181,12 +185,12 @@
 
 /**
  * versal_validate_power_state() - This function ensures that the power state
- * parameter in request is valid.
+ *                                 parameter in request is valid.
+ * @power_state: Power state of core.
+ * @req_state: Requested state.
  *
- * @power_state		Power state of core
- * @req_state		Requested state
+ * Return: Returns status, either success or reason.
  *
- * @return	Returns status, either success or reason
  */
 static int32_t versal_validate_power_state(uint32_t power_state,
 				       psci_power_state_t *req_state)
@@ -213,9 +217,9 @@
 }
 
 /**
- * versal_get_sys_suspend_power_state() -  Get power state for system suspend
+ * versal_get_sys_suspend_power_state() - Get power state for system suspend.
+ * @req_state: Requested state.
  *
- * @req_state	Requested state
  */
 static void versal_get_sys_suspend_power_state(psci_power_state_t *req_state)
 {