Revert "tty/serial: of_serial: add DT alias ID handling"

This reverts commit 6d01bb9dc8.

The exact same code was added in commit 3239fd31d4 (serial: of-serial: fetch
line number from DT) a few lined above. Doing this once should be enough.

Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/of_serial.c

@@ -133,10 +133,6 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
 	if (of_find_property(np, "no-loopback-test", NULL))
 		port->flags |= UPF_SKIP_TEST;
 
-	ret = of_alias_get_id(np, "serial");
-	if (ret >= 0)
-		port->line = ret;
-
 	port->dev = &ofdev->dev;
 
 	switch (type) {