serial: 8250: kill __do_stop_tx()

There seems to be little reason for __do_stop_tx() to exits on its own.
It is rather simple and is only called from __stop_tx(). Thus, move its
logic into __stop_tx().
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220607084154.8172-1-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_port.c

@@ -1503,12 +1503,6 @@ static void __stop_tx_rs485(struct uart_8250_port *p, u64 stop_delay)
 	}
 }
 
-static inline void __do_stop_tx(struct uart_8250_port *p)
-{
-	if (serial8250_clear_THRI(p))
-		serial8250_rpm_put_tx(p);
-}
-
 static inline void __stop_tx(struct uart_8250_port *p)
 {
 	struct uart_8250_em485 *em485 = p->em485;
@@ -1542,7 +1536,9 @@ static inline void __stop_tx(struct uart_8250_port *p)
 
 		__stop_tx_rs485(p, stop_delay);
 	}
-	__do_stop_tx(p);
+
+	if (serial8250_clear_THRI(p))
+		serial8250_rpm_put_tx(p);
 }
 
 static void serial8250_stop_tx(struct uart_port *port)