scsi: qla2xxx: Fix double increment of switch scan retry count

This patch fixes issue when switch command fails, current code increments
retry count twice. This results in a smaller number of retries.

Signed-off-by: Quinn Tran <quinn.tran@cavium.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>