scsi: pm80xx: Fixed system hang issue during kexec boot

[ Upstream commit 72349b62a571effd6faadd0600b8e657dd87afbf ]

When the firmware is not responding, execution of kexec boot causes a system
hang. When firmware assertion happened, driver get notified with interrupt
vector updated in MPI configuration table. Then, the driver will read
scratchpad register and set controller_fatal_error flag to true.

Signed-off-by: Deepak Ukey <deepak.ukey@microchip.com>
Signed-off-by: Viswas G <Viswas.G@microchip.com>
Acked-by: Jack Wang <jinpu.wang@profitbricks.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>