Update sync CDB code to handle io vectors

Remove code in sgio related to creating bio
Remove most of the bio processing functions
Fix the sync cdb completion code by adding timeout and dma unmap cvalls.
Cleanup sgio completion by changing parameters passed and calling this from sync completion
Init the sop request structure before issuing sync CDB
Remove code of SGIO from make_request path
Initialize the sync cdb request structure before issuing calls to get disk params
Fix the bug where sop request fields were reinitialized in sop_send_command function
Properly handle multiple sg creation in queue entry while issuing sync cdb
Return SCSI status as return value from return sync CDB
Add prints to probe to show different stages of loading
Change kcalloc parameter to allocate with no-wait. Cannot wait in sgio path for temporary memory alloc.
Remove sgio completion routine prototype declataion by moving the function body up
pre allocate page map so we do not have to use GFP_NOWAIT
Check for the return value from sync scatterlist preperation.
Clear the page link in each sg entry prepared for sync cdb, since no sg table init was done.
Also this code can be done in bio sg list preparation where the whole table was initialized every time.