s390/cio: fix return code after missing interrupt

When a timeout occurs for users of ccw_device_start_timeout
we will stop the IO and call the drivers int handler with
the irb pointer set to ERR_PTR(-ETIMEDOUT). Sometimes
however we'd set the irb pointer to ERR_PTR(-EIO) which is
not intended. Just set the correct value in all codepaths.

Reported-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>