scsi: clean obsolete return values of eh_timed_out

Those are no longer in use since commit 242f9dcb
("block: unify request timeout handling").

Signed-off-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>