xfs: introduce xfs_inode_buf.c for inode buffer operations

The only thing remaining in xfs_inode.[ch] are the operations that
read, write or verify physical inodes in their underlying buffers.
Move all this code to xfs_inode_buf.[ch] and so we can stop sharing
xfs_inode.[ch] with userspace.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index ce0b87e..7f2319d 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -75,6 +75,7 @@
 				   xfs_icreate_item.o \
 				   xfs_inode.o \
 				   xfs_inode_fork.o \
+				   xfs_inode_buf.o \
 				   xfs_log_recover.o \
 				   xfs_mount.o \
 				   xfs_symlink.o \