mm: remove MPOL_MF_STATS

mm: remove MPOL_MF_STATS

Mapping statistics in a NUMA environment is now computed using the generic
walk_page_range() logic.  Remove the old/equivalent functionality.

Signed-off-by: Stephen Wilson <[email protected]>
Reviewed-by: KOSAKI Motohiro <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Lee Schermerhorn <[email protected]>
Cc: Alexey Dobriyan <[email protected]>
Cc: Christoph Lameter <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>