GRU Driver: TLB flushing, MMUOPS callouts

This file contains the functions for handlinf GRU TLB flushing, This
includes functions to handle the MMUOPS callouts.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>