ncs36510: fix sleep/deepslep name - add prefix hal_

This resolves an error that sleep is already defined.

Author: 0xc0170

targets/TARGET_ONSEMI/TARGET_NCS36510/sleep_api.c

@@ -38,12 +38,12 @@
 #include "sleep_api.h"
 #include "cmsis_nvic.h"
 
-void sleep()
+void hal_sleep()
 {
     fncs36510_sleep();
 }
 
-void deepsleep()
+void hal_deepsleep()
 {
     fncs36510_deepsleep();
 }