megaraid_sas: JBOD sequence number support

megaraid_sas: JBOD sequence number support

Implemented JBOD map which will provide quick access for JBOD path and
also provide sequence number.  This will help hardware to fail command
to the FW in case of any sequence mismatch.

Fast Path I/O for JBOD will refer JBOD map (which has sequence number
per JBOD device) instead of RAID map.  Previously, the driver used RAID
map to get device handle for fast path I/O and this not have sequence
number information. Now, driver will use JBOD map instead.  As part of
error handling, if JBOD map is failed/not supported by firmware, driver
will continue using legacy behavior.

Now there will be three IO paths for JBOD (syspd):

 - JBOD map with sequence number (Fast Path)
 - RAID map without sequence number (Fast Path)
 - FW path via h/w exception queue deliberately setup devhandle
   0xFFFF (FW path).

Relevant data structures:

 - Driver send new DCMD MR_DCMD_SYSTEM_PD_MAP_GET_INFO for this purpose.
 - struct MR_PD_CFG_SEQ- This structure represent map of single physical
   device.
 - struct MR_PD_CFG_SEQ_NUM_SYNC- This structure represent whole JBOD
   map in general(size, count of sysPDs configured, struct MR_PD_CFG_SEQ
   of syspD with 0 index).
 - JBOD sequence map size is: sizeof(struct MR_PD_CFG_SEQ_NUM_SYNC)
   + (sizeof(struct MR_PD_CFG_SEQ) * (MAX_PHYSICAL_DEVICES - 1)) which
   is allocated while setting up JBOD map at driver load time.

Signed-off-by: Sumit Saxena <sumit.saxena@avagotech.com>
Signed-off-by: Kashyap Desai <kashyap.desai@avagotech.com>
Reviewed-by: Martin Petersen <martin.petersen@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>