mlxsw: spectrum: Simplify traps definition

Instead of copying & pasting the same struct initialization for every
Rx listener, just use a macro.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>