mlxsw: spectrum_trap: Remove unnecessary field

Now that traffic class (TC) and priority are set to the same value,
there is no need to store both. Remove the first.

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