numa_maps: remove numa_maps->vma

numa_maps: remove numa_maps->vma

pagewalk.c can handle vma in itself, so we don't have to pass vma via
walk->private.  And show_numa_map() walks pages on vma basis, so using
walk_page_vma() is preferable.

Signed-off-by: Naoya Horiguchi <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>