scsi: fnic: Adding debug IO and Abort latency counter to fnic stats

The IO and Abort latency counter counts the time taken to complete the
IO and abort command into broad buckets. This is not intended for
performance measurement, just a debug statistic.  current_max_io_time
tries to keep track of the maximum time an IO has taken to complete if
it is > 30sec.

Signed-off-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Sesidhar Baddela <sebaddel@cisco.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>