Extract cow_file_range() new parameters for both in-band dedupe and
subpage sector size patchset.

This should make conflict of both patchset to minimal, and reduce the
effort needed to rebase them.

Cc: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: NWang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: NQu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>