lkvm -i is currently broken on ARM/ARM64.
We should not try to convert smaller-than-4GB addresses into 64-bit
big endian and then stuff them into u32 variables if we expect to read
anything other than 0 out of it.
Adjust the type to u64 to write the proper address in BE format into
the /chosen node (and also match the address size we formely posted)
and let Linux thus read the right values.
This fixes initrd functionality for ARM and ARM64 guests.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>