This run away from previous set :) Two routines are now
identical, only page-read flags differ.

v2: Keep the uffd_hanle_pages() name

travis-ci: success for Some more cleanups over uffd.c (rev3)
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>