staging: rtl8723bs: Remove return statement from void function

Fix the following checkpatch warning:

"WARNING: void function return statements are not generally useful"
Signed-off-by: Leandro Ribeiro <leandrohr@riseup.net>
Link: https://lore.kernel.org/r/20190904210631.13599-1-leandrohr@riseup.netSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/hal/rtl8723b_cmd.c

@@ -1406,7 +1406,6 @@ void rtl8723b_set_ap_wowlan_cmd(struct adapter *padapter, u8 enable)
 	rtl8723b_set_Fw_AP_Offload_Cmd(padapter, enable);
 	msleep(10);
 	DBG_871X_LEVEL(_drv_always_, "-%s()-\n", __func__);
-	return ;
 }
 #endif /* CONFIG_AP_WOWLAN */