f2fs: update_sit_entry_for_release() supports consecutive blocks.

This function can process some consecutive blocks at a time.

When using update_sit_entry() to release consecutive blocks,
ensure that the consecutive blocks belong to the same segment.
Because after update_sit_entry_for_realese(), @segno is still
in use in update_sit_entry().

Signed-off-by: Yi Sun <yi.sun@unisoc.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>