scsi: mpt3sas: Enable interrupt coalescing on high iops

scsi: mpt3sas: Enable interrupt coalescing on high iops

Enable interrupt coalescing only on high iops queues.

In ioc config page 1, offset 0x14 (ProductSpecific field) is used to
determine interrupt coalescing enabled/disabled on per reply descriptor
post queue group(8) basis.  If 31st bit is zero, then interrupt coalescing
is enabled for all reply descriptor post queues. If 31st bit is set to one,
then user can enable/disable interrupt coalescing on per reply descriptor
post queue group(8) basis. So to enable interrupt coalescing only on first
reply descriptor post queue group (i.e. on high iops queues), set bit 0 and
31.

This configuration should reset during driver unload or shutdown to the
default settings. For this, the driver takes copy of default ioc page 1 and
copies back the default or unmodified ioc page1 during unload and
shutdown. This means that on next driver load (e.g. if older version driver
is loaded by user), current modified changes on ioc page1 won't take
effect.

Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>