tty: Char: mxser, use THRE for ASPP_OQUEUE ioctl

In moxa specific ASPP_OQUEUE ioctl command, they apparently want
only know whether there is space in transmitter hold register.

So switch UART_LSR_TEMT to UART_LSR_THRE in that specific case
according to the change in 1.14 moxa drivers.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/char/mxser.c

@@ -1806,7 +1806,7 @@ static int mxser_ioctl(struct tty_struct *tty, struct file *file,
 
 		lock_kernel();
 		len = mxser_chars_in_buffer(tty);
-		lsr = inb(info->ioaddr + UART_LSR) & UART_LSR_TEMT;
+		lsr = inb(info->ioaddr + UART_LSR) & UART_LSR_THRE;
 		len += (lsr ? 0 : 1);
 		unlock_kernel();