include/infiniband/ssa_db.h: adding API

include/infiniband/ssa_db.h: adding API for SMDB initialization

shared/ssa_db.c: API implementation

Signed-off-by: Ilya Nelkenbaum <ilyan@mellanox.com>
Signed-off-by: Ira Weiny <weiny2@llnl.gov>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>
ssa_db.h: Add define for reserved value to indicate no related table

Signed-off-by: Hal Rosenstock <hal@mellanox.com>