8250_men_mcb: Make UART config auto configurable

8250_men_mcb: Make UART config auto configurable

The UART ports created by this driver were not usable out of
the box, so let the configuration be handled by the 8250 UART
subsystem. This makes the implementation simpler and the UART
port more usable.

The 8250 UART subsystem will take care of requesting the memory
resources, but the driver needs to first read the register where
the num ports is set, so a request of the resource is needed
before registering the UART port.

Co-developed-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Javier Rodriguez <josejavier.rodriguez@duagon.com>
Link: https://lore.kernel.org/r/20230705131423.30552-4-josejavier.rodriguez@duagon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>