Bluetooth: hci_ldisc: Use speed set by btattach as oper_speed

Starting a BCM UART controller not defined as a platform device or
a serdev with "btattach -B /dev/ttyS1 -P bcm -S 3000000" works fine
but the serial port remains at the init_speed, i.e. 115200.

The oper_speed is only set if a device is declared in ACPI, device
tree or as a platform device.

This commit copies the serial port speed fixed by hciattach to the
oper_speed on line discipline opening.
Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

drivers/bluetooth/hci_ldisc.c

@@ -507,6 +507,9 @@ static int hci_uart_tty_open(struct tty_struct *tty)
 	hu->alignment = 1;
 	hu->padding = 0;
 
+	/* Use serial port speed as oper_speed */
+	hu->oper_speed = tty->termios.c_ospeed;
+
 	INIT_WORK(&hu->init_ready, hci_uart_init_work);
 	INIT_WORK(&hu->write_work, hci_uart_write_work);