[PATCH] IB/mthca: Split off MTT allocation

Split allocation of MTT range from creation of MR.  This will be useful for
implementing shared memory regions and userspace verbs.

Signed-off-by: Roland Dreier <roland@topspin.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>