staging: rtl8723bs: Replace NULL pointer comparison with '!'.

Replace the comparison of 'precvbuf' to 'NULL' with '!precvbuf'.
Signed-off-by: NQuytelda Kahja <quytelda@tamalin.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8723bs/hal/rtl8723bs_recv.c

@@ -259,7 +259,7 @@ static void rtl8723bs_recv_tasklet(void *priv)
 
 	do {
 		precvbuf = rtw_dequeue_recvbuf(recv_buf_queue);
-		if (NULL == precvbuf)
+		if (!precvbuf)
 			break;
 
 		ptr = precvbuf->pdata;