selftests: mlxsw: tc_restrictions: Test tc-police restrictions

Test that upper and lower limits on rate and burst size imposed by the
device are rejected by the kernel.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>