selftests: drv-net: rss_api: context create and delete tests

selftests: drv-net: rss_api: context create and delete tests

Add test cases for creating and deleting contexts.

  TAP version 13
  1..12
  ok 1 rss_api.test_rxfh_nl_set_fail
  ok 2 rss_api.test_rxfh_nl_set_indir
  ok 3 rss_api.test_rxfh_nl_set_indir_ctx
  ok 4 rss_api.test_rxfh_indir_ntf
  ok 5 rss_api.test_rxfh_indir_ctx_ntf
  ok 6 rss_api.test_rxfh_nl_set_key
  ok 7 rss_api.test_rxfh_fields
  ok 8 rss_api.test_rxfh_fields_set
  ok 9 rss_api.test_rxfh_fields_set_xfrm # SKIP no input-xfrm supported
  ok 10 rss_api.test_rxfh_fields_ntf
  ok 11 rss_api.test_rss_ctx_add
  ok 12 rss_api.test_rss_ctx_ntf
  # Totals: pass:11 fail:0 xfail:0 xpass:0 skip:1 error:0

Link: https://patch.msgid.link/20250717234343.2328602-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>