Some commands (loadb/x/y) rely on console_get_by_name, which searches the list
of console devices based on console_device->devname. However, some serial
drivers do not set devname, meaning that their respective console_devices can
never be found. During console_register, ensure that a default devname is set
if one is not already explicitly set.

Signed-off-by: David Dgien <dgienda125@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>