unifying the vma offset managers

So a passing comment on irc from Daniel made me look at this, and cleaning up some surrounding things. This unifies the GEM/TTM vma offset managers around a single one based on the TTM one. There is also a patch to cleanup the GEM code after this, and one to clean up some bits of TTM also. I've t

unifying the vma offset managers

So a passing comment on irc from Daniel made me look at this, and cleaning up some surrounding things. This unifies the GEM/TTM vma offset managers around a single one based on the TTM one. There is also a patch to cleanup the GEM code after this, and one to clean up some bits of TTM also. I've t