ipr: Clear interrupt on croc/crocodile when running with LSI

BugLink: http://bugs.launchpad.net/bugs/1611833

commit 54e430bb upstream.

If we fall back to using LSI on the Croc or Crocodile chip we need to
clear the interrupt so we don't hang the system.
Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/scsi/ipr.c

@@ -10095,6 +10095,7 @@ static int ipr_probe_ioa(struct pci_dev *pdev,
 		ioa_cfg->intr_flag = IPR_USE_MSI;
 	else {
 		ioa_cfg->intr_flag = IPR_USE_LSI;
+		ioa_cfg->clear_isr = 1;
 		ioa_cfg->nvectors = 1;
 		dev_info(&pdev->dev, "Cannot enable MSI.\n");
 	}