[XFS] Use xfs_inode_clean() in more places

Remove open coded checks for the whether the inode is clean and replace
them with an inlined function.

SGI-PV: 977461
SGI-Modid: xfs-linux-melb:xfs-kern:30503a

Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

diff --cc fs/xfs/xfs_inode.c
Simple merge

diff --cc fs/xfs/xfs_inode_item.h
Simple merge

diff --cc fs/xfs/xfs_vnodeops.c
Simple merge