NFS/localio: Stop further I/O upon hitting an error

NFS/localio: Stop further I/O upon hitting an error

If the call into the filesystem results in an I/O error, then the next
chunk of data won't be contiguous with the end of the last successful
chunk. So break out of the I/O loop and report the results.
Currently the localio code will do this for a short read/write, but not
for an error.

Fixes: 6a218b9c3183 ("nfs/localio: do not issue misaligned DIO out-of-order")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: Mike Snitzer <snitzer@kernel.org>