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

Remove now useless invalidate_page callback.
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc: iommu@lists.linux-foundation.org
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>