scsi: smartpqi: Add host level stream detection enable

Allow R5/R6 stream detection to be disabled/enabled using sysfs entry
enable_stream_detection.

Example usage:

lsscsi
[2:2:0:0]    storage Adaptec  3258P-32i /e     0010
 ^
 |
 +---- NOTE: here host is host2

find /sys -name \*enable_stream\*
/sys/devices/pci0000:36/0000:36:00.0/0000:37:00.0/0000:38:00.0/0000:39:00.0/host2/scsi_host/host2/enable_stream_detection
/sys/devices/pci0000:5b/0000:5b:00.0/0000:5c:00.0/host3/scsi_host/host3/enable_stream_detection

Current stream detection:
cat /sys/devices/pci0000:36/0000:36:00.0/0000:37:00.0/0000:38:00.0/0000:39:00.0/host2/scsi_host/host2/enable_stream_detection
1

Turn off stream detection:
echo 0 > /sys/devices/pci0000:36/0000:36:00.0/0000:37:00.0/0000:38:00.0/0000:39:00.0/host2/scsi_host/host2/enable_stream_detection

Turn on stream detection:
echo 1 > /sys/devices/pci0000:36/0000:36:00.0/0000:37:00.0/0000:38:00.0/0000:39:00.0/host2/scsi_host/host2/enable_stream_detection

Link: https://lore.kernel.org/r/161549376281.25025.1132304698441513738.stgit@brunhilda


Reviewed-by: Scott Benesh <scott.benesh@microchip.com>
Reviewed-by: Mike McGowen <mike.mcgowen@microchip.com>
Reviewed-by: Scott Teel <scott.teel@microchip.com>
Reviewed-by: Kevin Barnett <kevin.barnett@microchip.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Don Brace <don.brace@microchip.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>