net: mvpp2: cls: Fix memory leak in mvpp2_ethtool_cls_rule_ins()

net: mvpp2: cls: Fix memory leak in mvpp2_ethtool_cls_rule_ins()

In mvpp2_ethtool_cls_rule_ins(), the ethtool_rule is allocated by
ethtool_rx_flow_rule_create(). If the subsequent conversion to flow
type fails, the function jumps to the clean_rule label.

However, the clean_rule label only frees efs, skipping the cleanup
of ethtool_rule, which leads to a memory leak.

Fix this by jumping to the clean_eth_rule label, which properly calls
ethtool_rx_flow_rule_destroy() before freeing efs.

Compile tested only. Issue found using a prototype static analysis tool
and code review.

Fixes: f4f1ba18195d ("net: mvpp2: cls: Report an error for unsupported flow types")
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260123065716.2248324-1-zilin@seu.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>