scsi: pm80xx: Add sysfs attribute to track RAAE count

scsi: pm80xx: Add sysfs attribute to track RAAE count

A new sysfs variable 'ctl_raae_count' is being introduced that tells if the
controller is alive by indicating controller ticks. If on subsequent run we
see the ticks changing in RAAE count that indicates that controller is not
dead.

Using the 'ctl_raae_count' sysfs variable we can see ticks incrementing:

    linux-9saw:~# cat /sys/class/scsi_host/host*/ctl_raae_count
    0x00002245
    0x00002253
    0x0000225e

Link: https://lore.kernel.org/r/20210415103352.3580-4-Viswas.G@microchip.com
Acked-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Vishakha Channapattan <vishakhavc@google.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: Radha Ramachandran <radha@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>