scsi: pm80xx: Fix driver fatal dump failure

The function pm80xx_get_fatal_dump() has two issues that result in the
fatal dump not being able to complete successfully.

 1. Trying to collect fatal_logs from the application fails because we are
    not shifting the MEMBASE-II register properly. Once we read 64K region
    of data we have to shift the MEMBASE-II register and read the next
    chunk. Only then would we be able to get complete data.

 2. If a timeout occurs, our application will get stuck.

Link: https://lore.kernel.org/r/20210109123849.17098-6-Viswas.G@microchip.com
Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Viswas G <Viswas.G@microchip.com>
Signed-off-by: Ruksar Devadi <Ruksar.devadi@microchip.com>
Signed-off-by: Ashokkumar N <Ashokkumar.N@microchip.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>