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/common/include/pm_common.h b/plat/xilinx/common/include/pm_common.h
index af7ca87..c0308ab 100644
--- a/plat/xilinx/common/include/pm_common.h
+++ b/plat/xilinx/common/include/pm_common.h
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2013-2018, Arm Limited and Contributors. All rights reserved.
+ * Copyright (c) 2022-2023, Advanced Micro Devices, Inc. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -33,10 +34,11 @@
 				 TZ_VERSION_MINOR)
 
 /**
- * pm_ipi - struct for capturing IPI-channel specific info
- * @local_ipi_id	Local IPI agent ID
- * @remote_ipi_id	Remote IPI Agent ID
- * @buffer_base	base address for payload buffer
+ * struct pm_ipi - struct for capturing IPI-channel specific info.
+ * @local_ipi_id: Local IPI agent ID.
+ * @remote_ipi_id: Remote IPI Agent ID.
+ * @buffer_base: base address for payload buffer.
+ *
  */
 struct pm_ipi {
 	const uint32_t local_ipi_id;
@@ -45,11 +47,12 @@
 };
 
 /**
- * pm_proc - struct for capturing processor related info
- * @node_id	node-ID of the processor
- * @pwrdn_mask	cpu-specific mask to be used for power control register
- * @ipi		pointer to IPI channel structure
- *		(in APU all processors share one IPI channel)
+ * struct pm_proc - struct for capturing processor related info.
+ * @node_id: node-ID of the processor.
+ * @pwrdn_mask: cpu-specific mask to be used for power control register.
+ * @ipi: pointer to IPI channel structure.
+ *       (in APU all processors share one IPI channel)
+ *
  */
 struct pm_proc {
 	const uint32_t node_id;