mm/hmm: use a structure for update callback parameters

Use a structure to gather all the parameters for the update callback.
This make it easier when adding new parameters by avoiding having to
update all callback function signature.

The hmm_update structure is always associated with a mmu_notifier
callbacks so we are not planing on grouping multiple updates together.
Nor do we care about page size for the range as range will over fully
cover the page being invalidated (this is a mmu_notifier property).

Link: http://lkml.kernel.org/r/20181019160442.18723-6-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>