Add support for the FDMI-2 fabric switch feature.

Since FDMI-2 uses code from FDMI-1, some of the existing code
needed to be repaired to prevent fields from being overflowed.
Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Saurav Kashyap <saurav.kashyap@qlogic.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>