[xosc] always _enable_ external tcxo when enabling hf clock

XOSC_TCXO_SHUTDOWN_EN only control disabling

firmware/src/xosc.c

@@ -74,9 +74,7 @@ void hf_clock_enable(void)
 
   /* Enable TCXO if required */
 #ifdef SI4xxx_TCXO_REG_EN_PIN
-#if XOSC_TCXO_SHUTDOWN_EN
   port_pin_set_output_level(SI4xxx_TCXO_REG_EN_PIN, 1);
-#endif
 #endif
 
   /* Setup XOSC  */