zynqmp: pm: Cleanup for clock set/get rate EEMI API

Clock set/get rate are not implemented and will likely never be.
Remove empty function stubs.

Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>
Acked-by: Will Wong <WILLW@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>
diff --git a/plat/xilinx/zynqmp/pm_service/pm_api_sys.c b/plat/xilinx/zynqmp/pm_service/pm_api_sys.c
index 402b7c6..eb54bcb 100644
--- a/plat/xilinx/zynqmp/pm_service/pm_api_sys.c
+++ b/plat/xilinx/zynqmp/pm_service/pm_api_sys.c
@@ -1060,7 +1060,7 @@
 enum pm_ret_status pm_clock_setrate(unsigned int clock_id,
 				    uint64_t rate)
 {
-	return pm_api_clock_setrate(clock_id, rate);
+	return PM_RET_ERROR_NOTSUPPORTED;
 }
 
 /**
@@ -1076,7 +1076,7 @@
 enum pm_ret_status pm_clock_getrate(unsigned int clock_id,
 				    uint64_t *rate)
 {
-	return pm_api_clock_getrate(clock_id, rate);
+	return PM_RET_ERROR_NOTSUPPORTED;
 }
 
 /**