memory: hugepages: map numa node IDs to host and guest correctly
foreach_dimm() provides a guest numa node index, when used
in conjunction with the guest-to-host numa node topology
mapping one has to make sure that the correct host-side
indices are used.
This covers situations where the user defines a numaX with
hostnodes=Y with Y != X.
Both numa IDs 1 and 2 passed by foreach_dimm() have to be
mapped to host node 0.
Note that this also reverses the foreach_reverse_dimm() numa
node numbering as the current code, while walking sizes
backwards, walked the numa IDs inside each size forward,
which makes more sense. (Memory hot-unplug is still working
with this.)