Btrfs: add inode item

Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --cc fs/btrfs/Makefile
Simple merge

diff --cc fs/btrfs/TODO
Simple merge

diff --cc fs/btrfs/ctree.h
Simple merge

diff --cc fs/btrfs/file-item.c
Simple merge

diff --cc fs/btrfs/inode-item.c
Simple merge