selftests: drivers: hw: Include tc_common.sh in hw_stats_l3

The tests use the constant TC_HIT_TIMEOUT when waiting on the counter
values. However it does not include tc_common.sh where the counter is
specified. The test has been robust in our testing, which means the counter
is bumped quickly enough that the updated value is available already on the
first iteration. Nevertheless it's not correct. Include tc_common.sh as
appropriate.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

selftests: forwarding: Ditch skip_on_veth()

Since the selftests that are not supposed to run on veth pairs are now in
their own dedicated directory, the skip_on_veth logic can go away. Drop it
from the selftests, and from lib.sh.

Cc: Danielle Ratson <danieller@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/63b470e10d65270571ee7de709b31672ce314872.1711464583.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

selftests: forwarding: Move several selftests

The tests in net/forwarding are generally expected to be HW-independent.
There are however several tests that, while not depending on any HW in
particular, nevertheless depend on being used on HW interfaces. Placing
these selftests to net/forwarding is confusing, because the selftest will
just report it can't be run on veth pairs. At the same time, placing them
to a particular driver's selftests subdirectory would be wrong.

Instead, add a new directory, drivers/net/hw, where these generic but HW
independent selftests should be placed. Move over several such tests
including one helper library.

Since typically these tests will not be expected to run, omit the directory
drivers/net/hw from the TARGETS list in selftests/Makefile. Retain a
Makefile in the new directory itself, so that a user can make -C into that
directory and act on those tests explicitly.

Cc: Roger Quadros <rogerq@kernel.org>
Cc: Tobias Waldekranz <tobias@waldekranz.com>
Cc: Danielle Ratson <danieller@nvidia.com>
Cc: Davide Caratti <dcaratti@redhat.com>
Cc: Johannes Nixdorf <jnixdorf-oss@avm.de>
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Link: https://lore.kernel.org/r/e11dae1f62703059e9fc2240004288ac7cc15756.1711464583.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>