zynqmp: pm: Correct function header of clock APIs

Correct function header of pm_api_clock_getparent() and
pm_api_clock_setparent().

Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Acked-by: Will Wong <WILLW@xilinx.com>
diff --git a/plat/xilinx/zynqmp/pm_service/pm_api_clock.c b/plat/xilinx/zynqmp/pm_service/pm_api_clock.c
index cecd558..b175b78 100644
--- a/plat/xilinx/zynqmp/pm_service/pm_api_clock.c
+++ b/plat/xilinx/zynqmp/pm_service/pm_api_clock.c
@@ -2965,7 +2965,7 @@
 /**
  * pm_api_clock_setparent - Set the clock parent for given id
  * @clock_id	Id of the clock
- * @parent_id	parent id
+ * @parent_idx	parent index
  *
  * This function is used by master to set parent for any clock.
  *
@@ -3016,7 +3016,7 @@
 /**
  * pm_api_clock_getparent - Get the clock parent for given id
  * @clock_id	Id of the clock
- * @parent_id	parent id
+ * @parent_idx	parent index
  *
  * This function is used by master to get parent index
  * for any clock.