mmu-notifiers: remove mmu notifier calls in apply_to_page_range()

mmu-notifiers: remove mmu notifier calls in apply_to_page_range()

It is not appropriate for apply_to_page_range() to directly call any mmu
notifiers, because it is a general purpose function whose effect depends
on what context it is called in and what the callback function does.

In particular, if it is being used as part of an mmu notifier
implementation, the recursive calls can be particularly problematic.

It is up to apply_to_page_range's caller to do any notifier calls if
necessary.  It does not affect any in-tree users because they all operate
on init_mm, and mmu notifiers only pertain to usermode mappings.

[[email protected]: remove unused local `start']
Signed-off-by: Jeremy Fitzhardinge <[email protected]>
Signed-off-by: Stefano Stabellini <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Stefano Stabellini <[email protected]>
Cc: Avi Kivity <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>