IB/SA: Introduce path record specific types

struct sa_path_rec has a gid_type field. This patch introduces a more
generic path record specific type 'rec_type' which is either IB, ROCE v1
or ROCE v2. The patch also provides conversion functions to get
a gid type from a path record type and vice versa

Reviewed-by: Don Hiatt <don.hiatt@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>