efm32: remove unused undefined function from rtc

Author: 0xc0170

targets/TARGET_Silicon_Labs/TARGET_EFM32/lp_ticker.c

@@ -128,19 +128,6 @@ void lp_ticker_free()
     RTC_FreezeEnable(false);
 }
 
-void rtc_set_comp0_value(uint64_t value, bool enable)
-{
-    rtc_enable_comp0(false);
-
-    /* Set callback */
-    RTC_FreezeEnable(true);
-    extended_comp0 = (uint32_t) (value >> RTC_BITS);
-    RTC_CompareSet(0, (uint32_t) (value & RTC_MAX_VALUE));
-    RTC_FreezeEnable(false);
-
-    rtc_enable_comp0(enable);
-}
-
 void lp_ticker_set_interrupt(timestamp_t timestamp)
 {
     RTC_IntDisable(RTC_IF_COMP0);