btrfs: pass a reloc_control to relocate_file_extent_cluster()

Instead of passing in a reloc_control's data_inode and
file_extent_cluster members, pass in the whole reloc_control structure.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>