Restore lp_ticker_free to previous implementation when running with uvisor

This is a temporary patch until uvisor is removed

Author: Oren Cohen

targets/TARGET_Freescale/TARGET_MCUXpresso_MCUS/api/lp_ticker.c

@@ -117,4 +117,12 @@ void lp_ticker_clear_interrupt(void)
     LPTMR_ClearStatusFlags(LPTMR0, kLPTMR_TimerCompareFlag);
 }
 
+void lp_ticker_free(void)
+{
+#ifndef  FEATURE_UVISOR
+    LPTMR_DisableInterrupts(LPTMR0, kLPTMR_TimerInterruptEnable);
+    NVIC_DisableIRQ(LPTMR0_IRQn);
+#endif
+}
+
 #endif /* DEVICE_LPTICKER */