cpu: native: remove hwtimer traces

cpu/native/include/native_internal.h

@@ -65,7 +65,6 @@ typedef void (*_native_callback_t)(void);
  */
 void native_cpu_init(void);
 void native_interrupt_init(void);
-extern void native_hwtimer_pre_init(void);
 
 void native_irq_handler(void);
 extern void _native_sig_leave_tramp(void);

cpu/native/include/periph_conf.h

@@ -48,8 +48,12 @@
 #define TIMER_NUMOF        (1U)
 #define TIMER_0_EN         1
 
-/** @def set TIMER0 for hwtimer wrapper */
-#define HW_TIMER TIMER_0
+/**
+ * @brief xtimer configuration
+ * @{
+ */
+#define XTIMER_OVERHEAD 14
+#define XTIMER_USLEEP_UNTIL_OVERHEAD 1
 /** @} */
 
 #ifdef __cplusplus