The ram_limit field was imported from sPAPREnvironment where it predates
the machine's ram size being available generically from machine->ram_size.
Worse, the existing code was inconsistent about where it got the ram size
from. Sometimes it used spapr->ram_limit, sometimes the global 'ram_size'
and sometimes a local 'ram_size' masking the global.
This cleans up the code to consistently use machine->ram_size, eliminating
spapr->ram_limit in the process.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>