scsi: dpt_i2o: Add a missing call to kfree

Most error branches following the call to kzalloc contain a call to
kfree. This patch add these calls where they are missing.

This issue was found with Hector.

Signed-off-by: Quentin Lambert <lambert.quentin@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>