migration/ram: Fix populate_read_range()

migration/ram: Fix populate_read_range()

Unfortunately, commit f7b9dcfbcf44 broke populate_read_range(): the loop
end condition is very wrong, resulting in that function not populating the
full range. Lets' fix that.

Fixes: f7b9dcfbcf44 ("migration/ram: Factor out populating pages readable in ram_block_populate_pages()")
Cc: qemu-stable@nongnu.org
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>