[][kernel][common][eth][Fix Coverity scan warning]

[Description]
Fix Coverity scan warning for the uninitialized variable
in the mtk_mdc_init().

[Release-log]
N/A


Change-Id: I440dc23f1fbc2e1a5cf86afdd1112d77156819aa
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7398188
diff --git a/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index ad73fdb..b4890fe 100755
--- a/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/target/linux/mediatek/files-5.4/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1096,7 +1096,7 @@
 {
 	struct device_node *mii_np;
 	int max_clk = 2500000, divider;
-	int ret;
+	int ret = 0;
 	u32 val;
 
 	mii_np = of_get_child_by_name(eth->dev->of_node, "mdio-bus");