hpsa: disable report lun data caching

When external target arrays are present, disable the firmware's
normal behavior of returning a cached copy of the report lun data,
and force it to collect new data each time we request a report luns.

This is necessary for external arrays, since there may be no
reliable signal from the external array to the smart array when
lun configuration changes, and thus when driver requests
report luns, it may be stale data.

Use diag options to turn off RPL data caching.

Reviewed-by: Scott Teel <scott.teel@pmcs.com>
Reviewed-by: Justin Lindley <justin.lindley@pmcs.com>
Reviewed-by: Kevin Barnett <kevin.barnett@pmcs.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Don Brace <don.brace@pmcs.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>