staging: rtl8723au: core: rtw_pwrctrl: Fix void function return statements style warning.

The following patch fixes the checkpatch.pl warning:

drivers/staging/rtl8723au/core/rtw_pwrctrl.c WARNING: void function return statements are not generally useful
Signed-off-by: NYeliz Taneroglu <yeliztaneroglu@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723au/core/rtw_pwrctrl.c

@@ -172,7 +172,6 @@ void rtw_ps_processor23a(struct rtw_adapter *padapter)
 exit:
 	rtw_set_pwr_state_check_timer(&padapter->pwrctrlpriv);
 	pwrpriv->ps_processing = false;
-	return;
 }
 
 static void pwr_state_check_handler(unsigned long data)