staging: rtl8723bs: Replace yield() call with cond_resched()

Remove yield call(). yield does not guarantee progress, and should not
be used. cond_resched() is a safe alternative.
Signed-off-by: NThomas Avery <tavery321@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/core/rtw_mlme_ext.c

@@ -4263,7 +4263,7 @@ unsigned int send_beacon(struct adapter *padapter)
 		issue_beacon(padapter, 100);
 		issue++;
 		do {
-			yield();
+			cond_resched();
 			rtw_hal_get_hwreg(padapter, HW_VAR_BCN_VALID, (u8 *)(&bxmitok));
 			poll++;
 		} while ((poll%10) != 0 && false == bxmitok && !padapter->bSurpriseRemoved && !padapter->bDriverStopped);