selftests: drv-net: rss_ctx: test queue changes vs user RSS config

By default main RSS table should change to include all queues.
When user sets a specific RSS config the driver should preserve it,
even when queue count changes. Driver should refuse to deactivate
queues used in the user-set RSS config.

For additional contexts driver should still refuse to deactivate
queues in use. Whether the contexts should get resized like
context 0 when queue count increases is a bit unclear. I anticipate
most drivers today don't do that. Since main use case for additional
contexts is to set the indir table - it doesn't seem worthwhile to
care about behavior of the default table too much. Don't test that.

Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20240708213627.226025-4-kuba@kernel.org


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