eth: mtk_eth_soc: silence the GCC 12 array-bounds warning

GCC 12 gets upset because in mtk_foe_entry_commit_subflow()
this driver allocates a partial structure. The writes are
within bounds.

Silence these warnings for now, our build bot runs GCC 12
so we won't allow any new instances.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mediatek/Makefile

@@ -11,3 +11,8 @@ mtk_eth-$(CONFIG_NET_MEDIATEK_SOC_WED) += mtk_wed_debugfs.o
 endif
 obj-$(CONFIG_NET_MEDIATEK_SOC_WED) += mtk_wed_ops.o
 obj-$(CONFIG_NET_MEDIATEK_STAR_EMAC) += mtk_star_emac.o
+
+# FIXME: temporarily silence -Warray-bounds on non W=1+ builds
+ifndef KBUILD_EXTRA_WARN
+CFLAGS_mtk_ppe.o += -Wno-array-bounds
+endif