powerpc/powernv: update to new mmu_notifier semantic

powerpc/powernv: update to new mmu_notifier semantic

Calls to mmu_notifier_invalidate_page() were replaced by calls to
mmu_notifier_invalidate_range() and now are bracketed by calls to
mmu_notifier_invalidate_range_start()/end()

Remove now useless invalidate_page callback.

Signed-off-by: Jérôme Glisse <[email protected]>
Cc: [email protected]
Cc: Alistair Popple <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Kirill A. Shutemov <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>