[SCSI] scsi_dh_rdac: Add support for Sun StorageTek ST2500, ST2510 and ST2530

These storage arrays can use RDAC when configured with 'linux' as the
initiator.

http://www.sun.com/storage/disk_systems/workgroup/2500/
http://www.sun.com/storage/disk_systems/workgroup/2510/
http://www.sun.com/storage/disk_systems/workgroup/2530/



Signed-off-by: Charlie Brady <charlieb@budge.apana.org.au>
Reviewed-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>