Add ssa_smdb.h link in distrib directory

Signed-off-by: Ilya Nelkenbaum <ilyan@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>
Add ssa_smdb.h link in plugin/core

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