HAL_SITL: removed hal.util->new_semaphore()

replaced with HAL_Semaphore

libraries/AP_HAL_SITL/Util.h

@@ -22,9 +22,6 @@ public:
         return 0x20000;
     }
 
-    // create a new semaphore
-    AP_HAL::Semaphore *new_semaphore(void) override { return new HALSITL::Semaphore; }
-
     // get path to custom defaults file for AP_Param
     const char* get_custom_defaults_file() const override {
         return sitlState->defaults_path;