[SCSI] ipr: add workaround for MSI interrupts on P7

This patch adds some additional logic to the interrupt service routine to fix
a potential problem where an MSI interrupt does not get cleared the first time.

Signed-off-by: Wayne Boyer <wayneb@linux.vnet.ibm.com>
Acked-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/ipr.h

@@ -144,6 +144,7 @@
 #define IPR_IOA_MAX_SECTORS				32767
 #define IPR_VSET_MAX_SECTORS				512
 #define IPR_MAX_CDB_LEN					16
+#define IPR_MAX_HRRQ_RETRIES				3
 
 #define IPR_DEFAULT_BUS_WIDTH				16
 #define IPR_80MBs_SCSI_RATE		((80 * 10) / (IPR_DEFAULT_BUS_WIDTH / 8))