xfs: make xfs_iomap_write_direct() report an error to xfs_trans_cancel

I've been in the situation a few times where the transaction got
cancelled by some reason. Most of time because bmapi_write failed and I
start a guessing game trying to understand why.

So if xfs_iomap_write_direct fails and it causes the transaction to be
cancelled, send the error to xfs_trans_cancel so the error gets logged
into the kernel log buffer.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>