selftests: drv-net: rss_ctx: don't fail reconfigure test if queue offset not supported

Vast majority of drivers does not support queue offset.
Simply return if the rss context + queue ntuple fails.

Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20250201013040.725123-5-kuba@kernel.org


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