scsi: mpt3sas: Gracefully handle online firmware update

scsi: mpt3sas: Gracefully handle online firmware update

Issue:

During online Firmware upgrade operations it is possible that MaxDevHandles
filled in IOCFacts may change with new FW.  With this we may observe kernel
panics when driver try to access the pd_handles or blocking_handles buffers
at offset greater than the old firmware's MaxDevHandle value.

Fix:

_base_check_ioc_facts_changes() looks for increase/decrease in IOCFacts
attributes during online firmware upgrade and increases the pd_handles,
blocking_handles, etc buffer sizes to new firmware's MaxDevHandle value if
this new firmware's MaxDevHandle value is greater than the old firmware's
MaxDevHandle value.

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