An I/O can be in any state when flush is called, it can be in abort,
waiting for abort, RRQ send and waiting or TMF send.

 - HZ can be different on different architecture, correctly set abort
   timeout value.

 - Flush can complete the I/Os prematurely, handle refcount for aborted
   I/Os and for which RRQ is pending.

 - Differentiate LUN/TARGET reset, as cleanup needs to be send to firmware
   accordingly.

 - Add flush mutex to sync cleanup call from abort and flush routine.

 - Clear abort/outstanding bit on timeout.
Signed-off-by: Shyam Sundar <shyam.sundar@marvell.com>
Signed-off-by: Chad Dupuis <cdupuis@marvell.com>
Signed-off-by: Saurav Kashyap <skashyap@marvell.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>