net: ethernet: mtk_ppe: Fix rhashtable leak in mtk_ppe_init error paths

net: ethernet: mtk_ppe: Fix rhashtable leak in mtk_ppe_init error paths

In mtk_ppe_init(), when accounting is enabled, the error paths for
dmam_alloc_coherent(mib) and devm_kzalloc(acct) failures return NULL
directly, bypassing the err_free_l2_flows label that destroys the
rhashtable initialized earlier.

While this leak only occurs during probe (not runtime) and the leaked
memory is minimal (an empty rhash table), fixing it ensures proper
error path cleanup consistency.

Fix by changing the two return NULL statements to goto err_free_l2_flows.

Fixes: 603ea5e7ffa7 ("net: ethernet: mtk_eth_soc: fix memory leak in error path")
Signed-off-by: Wayen Yan <win847@gmail.com>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/178167550101.2217645.14579307712717502425@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>