serial: 8250_dw: allow lower reference frequencies

We have couple of standard but rare used baudrates which are not supported by
1,8432MHz reference frequency. Besides that user can potentially ask for any
baudrate (via BOTHER flag) and we currently don't fully support that. Since
clk-fractional-divider is moved to use rational best approximation for
reference frequency we may amend the driver to support whatever user wants.
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>

drivers/tty/serial/8250/8250_dw.c

@@ -224,10 +224,6 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
 	if (IS_ERR(d->clk) || !old)
 		goto out;
 
-	/* Not requesting clock rates below 1.8432Mhz */
-	if (baud < 115200)
-		baud = 115200;
-
 	clk_disable_unprepare(d->clk);
 	rate = clk_round_rate(d->clk, baud * 16);
 	ret = clk_set_rate(d->clk, rate);