[SCSI] qla4xxx: Removed residual from overrun debug print

The residual variable is only valid for udnerrun so do
not print it out for the overrun case.

Signed-off-by: Karen Higgins <karen.higgins@qlogic.com>
[Mike Christie: Fix coding style issues in patch]
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>