liquidio: improve soft command handling

liquidio: improve soft command handling

1. Set LIO_SC_MAX_TMO_MS as the maximum timeout value for a soft command
   (sc).  All sc's use this value as a hard timeout value. Add expiry_time
   in struct octeon_soft_command to keep the hard timeout value. The field
   wait_time and timeout in struct octeon_soft_command will be obsoleted in
   the last patch of this patch series.
2. Add processing a synchronous sc in sc response thread
   lio_process_ordered_list. The memory allocated for a synchronous sc will
   be freed by lio_process_ordered_list() to the sc pool.
3. Add two response lists for lio_process_ordered_list to process the
   storage allocated for sc's:
   OCTEON_DONE_SC_LIST response list keeps all sc's which will be freed to
   the pool after their requestors have finished processing the responses.
   OCTEON_ZOMBIE_SC_LIST response list keeps all sc's which have got
   LIO_SC_MAX_TMO_MS timeout.
   When an sc gets a hard timeout, lio_process_order_list() will recheck
   its status 1 ms later. If the status has not updated by the firmware at
   that time, the sc will be removed from OCTEON_DONE_SC_LIST response list
   to OCTEON_ZOMBIE_SC_LIST response list. The sc's in the
   OCTEON_ZOMBIE_SC_LIST response list will be freed when the driver is
   unloaded.

Signed-off-by: Weilin Chang <weilin.chang@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>