staging: greybus: uart: fix TIOCGSERIAL flags

This driver does not have a low-latency mode and should not report
anything else.

Also drop the skip-test flag which isn't used either.
Signed-off-by: Johan Hovold <johan@kernel.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/uart.c

@@ -624,7 +624,6 @@ static int get_serial_info(struct gb_tty *gb_tty,
 	struct serial_struct tmp;
 
 	memset(&tmp, 0, sizeof(tmp));
-	tmp.flags = ASYNC_LOW_LATENCY | ASYNC_SKIP_TEST;
 	tmp.type = PORT_16550A;
 	tmp.line = gb_tty->minor;
 	tmp.xmit_fifo_size = 16;