Remove the memory manager parameter from the put_block function, as this
makes the client code a lot cleaner. Prepare buffer manager for lock and
unlock calls.
Fix buggy aligned allocations.
Remove the stupid root_node field from the core memory manager.
Support multi-page buffer offset alignments
Add improved alignment functionality to the core memory manager.
This makes an allocated block actually align itself and returns any
wasted space to the manager.

Signed-off-by: Dave Airlie <airlied@linux.ie>