proc: make struct proc_maps_private truly private

proc: make struct proc_maps_private truly private

Now that mm/mempolicy.c is no longer implementing /proc/pid/numa_maps
there is no need to export struct proc_maps_private to the world.  Move it
to fs/proc/internal.h instead.

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]>