serial: copy UART properties of UPF_FIXED_TYPE ports provisioned using early_serial_setup

Augment the UPF_FIXED_TYPE logic, which currently applies to UART ports
provisioned using platform_device_register.

The suggested patch applies same logic into 'serial8250_register_ports',
making UART ports provisioned using early_serial_setup inherit their
properties from the uart_config entry.

Signed-off-by: Shmulik Ladkani <shmulik@jungo.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>