mpt3sas: Added mpt2sas driver definitions

1. Added mpt2sas driver related macros in mpt3sas header files

2. Made scsi host's, raid class', pci's, ioctl's callback functions
global so that both drivers can use them.

Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>