[SCSI] ipr: ipr_test_msi() fails when running with msi-x enabled adapter

Loading ipr modules failed(-22) with msi-x enabled adapter. In ipr_test_msi(),
We need to pass the first vector of msix vectors instead of using pdev->irq
to request_irq() when adapter enables msix feature.

Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>