libxfs: add more list operations

libxfs: add more list operations

Add some list operations that the deferred rmap code requires.

Code comes from the following kernel files:
lib/list_sort.c for all the list_sort stuff,
include/linux/list.h for the rest of the list_* stuff,
include/linux/kernel.h for container_of.

[ dchinner: move list_sort code to libxfs/list_sort.c ]

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>