GRU Driver: resource management

This file contains functions realted to managing GRU resources provided to
the user.  Examples include GRU context assignment, load, unload,
migration, etc..
Signed-off-by: NJack Steiner <steiner@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>