selftests: fib offload: use sensible tos values

Although both iproute2 and the kernel accept 1 and 2 as tos values for
new routes, those are invalid. These values only set ECN bits, which
are ignored during IPv4 fib lookups. Therefore, no packet can actually
match such routes. This selftest therefore only succeeds because it
doesn't verify that the new routes do actually work in practice (it
just checks if the routes are offloaded or not).

It makes more sense to use tos values that don't conflict with ECN.
This way, the selftest won't be affected if we later decide to warn or
even reject invalid tos configurations for new routes.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/5e43b343720360a1c0e4f5947d9e917b26f30fbf.1643826556.git.gnault@redhat.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>