dm-crypt: start allocating with MAX_ORDER

dm-crypt: start allocating with MAX_ORDER

[ Upstream commit 13648e04a9b831b3dfa5cf3887dfa6cf8fe5fe69 ]

Commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely")
changed the meaning of MAX_ORDER from exclusive to inclusive. So, we
can allocate compound pages with up to 1 << MAX_ORDER pages.

Reflect this change in dm-crypt and start trying to allocate compound
pages with MAX_ORDER.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>