selftests: net: Adapt ethtool mq tests to fix in qdisc graft

Because of patch[1] the graft behaviour changed

So the command:

tcq replace parent 100:1 handle 204:

Is no longer valid and will not delete 100:4 added by command:

tcq replace parent 100:4 handle 204: pfifo_fast

So to maintain the original behaviour, this patch manually deletes 100:4
and grafts 100:1

Note: This change will also work fine without [1]

[1] https://lore.kernel.org/netdev/20250111151455.75480-1-jhs@mojatatu.com/T/#u

Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: vbnogueira

tools/testing/selftests/drivers/net/netdevsim/tc-mq-visibility.sh

@@ -58,9 +58,12 @@ for root in mq mqprio; do
     ethtool -L $NDEV combined 4
     n_child_assert 4 "One real queue, rest default"
 
-    # Graft some
-    tcq replace parent 100:1 handle 204:
-    n_child_assert 3 "Grafted"
+    # Remove real one
+    tcq del parent 100:4 handle 204:
+
+    # Replace default with pfifo
+    tcq replace parent 100:1 handle 205: pfifo limit 1000
+    n_child_assert 3 "Deleting real one, replacing default one with pfifo"
 
     ethtool -L $NDEV combined 1
     n_child_assert 1 "Grafted, one"