ARM: debug-ll: add default address for digicolor

The digicolor platform has three UARTs, but the Kconfig.debug
file explicitly lists port zero as the one to be used for the
console, while not providing any default values.

This can get an automated randconfig build stuck in a loop
waiting for the user to input the number. As we already know
the physical address, this patch provides that number as
default, along with a reasonable default value for the virtual
address.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Olof Johansson <olof@lixom.net>