[SCSI] bfa: enable basic PBC support

The patch includes the driver side changes to enable basic PBC (PreBoot
Configuration) feature.
- Data structure changes and new definitions for PBC.
- APIs to access PBC info.
- Remove unused code.

Signed-off-by: Jing Huang <huangj@brocade.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>