xfs: refactor common transaction/inode/quota allocation idiom

xfs: refactor common transaction/inode/quota allocation idiom

Source kernel commit: 3a1af6c317d0a55524f39079183be107be4c1f39

Create a new helper xfs_trans_alloc_inode that allocates a transaction,
locks and joins an inode to it, and then reserves the appropriate amount
of quota against that transction.  Then replace all the open-coded
idioms with a single call to this helper.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>