selftests: drv-net: Enable ntuple-filters if supported

selftests: drv-net: Enable ntuple-filters if supported

Certain devices which support ntuple-filters do not enable the feature
by default. The existing tests will skip (if they check for the feature),
or fail if they blindly attempt to install rules. Therefore, attempt to turn
on ntuple-filters if the device supports them.

Signed-off-by: Dimitri Daskalakis <daskald@meta.com>
Reviewed-by: Joe Damato <joe@dama.to>
Link: https://patch.msgid.link/20260430165217.3700469-1-dimitri.daskalakis1@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>