[SCSI] qla2xxx: fix timeout in qla2x00_down_timeout

iterations is unsigned, so it is impossible to get out of the loop
and return -ETIMEDOUT.

Signed-off-by: Bill Nottingham <notting@redhat.com>
Acked-by: Seokmann Ju <seokmann.ju@qlogic.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>