serial: fsl_lpuart: fix maximum acceptable baud rate with over-sampling

[ Upstream commit 815d835b7ba46685c316b000013367dacb2b461b ]

Using over-sampling ratio, lpuart can accept baud rate upto uartclk / 4.
Signed-off-by: NTomonori Sakita <tomonori.sakita@sord.co.jp>
Signed-off-by: NAtsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>

drivers/tty/serial/fsl_lpuart.c

@@ -1695,7 +1695,7 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
 	}
 
 	/* ask the core to calculate the divisor */
-	baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 16);
+	baud = uart_get_baud_rate(port, termios, old, 50, port->uartclk / 4);
 
 	spin_lock_irqsave(&sport->port.lock, flags);