We want only pages from given range in page_cache_seek_hole_data().  Use
pagevec_lookup_range() instead of pagevec_lookup() and remove
unnecessary code.

Note that the check for getting less pages than desired can be removed
because index gets updated by pagevec_lookup_range().

Link: http://lkml.kernel.org/r/20170726114704.7626-9-jack@suse.czSigned-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>