Adding support for raid transport layer. This will provide sysfs attributes
containing raid level, state, and resync rate.
MPT2SAS module will select RAID_ATTRS.
Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com> Reviewed-by: Eric Moore <eric.moore@lsi.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>