[][kernel][common][eth][Fix Intel X550 IOT issue]

[Description]
Fix Intel X550 IOT issue.

Due to X550 doesn't advertise 2.5G/5G link capability, phlylink
cannot resolve link speed/duplex in the phy_resolve_aneg_linkmode().
Therefore, we handle the link speed from vendor registers.

If without this patch, phylink will show unknown speed messages
when link with NBASE-T link partner.

[Release-log]
N/A


Change-Id: Iaef49fe8ea6ef7c6dc022e50456903b7feb4eef6
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/6852800
diff --git a/target/linux/mediatek/patches-5.4/747-net-phy-aquantia-add-AQR113C.patch b/target/linux/mediatek/patches-5.4/747-net-phy-aquantia-add-AQR113C.patch
index 4842524..8d01cab 100644
--- a/target/linux/mediatek/patches-5.4/747-net-phy-aquantia-add-AQR113C.patch
+++ b/target/linux/mediatek/patches-5.4/747-net-phy-aquantia-add-AQR113C.patch
@@ -10,6 +10,20 @@
  
  #define MDIO_PHYXS_VEND_IF_STATUS		0xe812
  #define MDIO_PHYXS_VEND_IF_STATUS_TYPE_MASK	GENMASK(7, 3)
+@@ -352,6 +352,13 @@ static int aqr107_read_status(struct phy_device *phydev)
+ 		break;
+ 	}
+ 
++	/* Handle the case when the link speed is unknown */
++	if (phydev->speed == SPEED_UNKNOWN) {
++		val = aqr107_read_rate(phydev);
++		if (val < 0)
++			return val;
++	}
++
+ 	val = aqr107_read_downshift_event(phydev);
+ 	if (val <= 0)
+ 		return val;
 @@ -695,6 +696,24 @@ static struct phy_driver aqr_driver[] = {
  	.ack_interrupt	= aqr_ack_interrupt,
  	.read_status	= aqr_read_status,