net: phy: fix reading fixed phy status

With the switch to phy_resolve_aneg_linkmode() we don't read from the
chip any longer what is advertised but use phydev->advertising directly.
For a fixed phy however this bitmap is empty so far, what results in
no common mode being found. This breaks DSA. Fix this by advertising
everything that is supported. For a normal phy this done by phy_probe().

Fixes: 5502b218 ("net: phy: use phy_resolve_aneg_linkmode in genphy_read_status")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/fixed_phy.c

@@ -22,6 +22,7 @@
 #include <linux/seqlock.h>
 #include <linux/idr.h>
 #include <linux/netdevice.h>
+#include <linux/linkmode.h>
 
 #include "swphy.h"
 
@@ -300,6 +301,8 @@ static struct phy_device *__fixed_phy_register(unsigned int irq,
 				 phy->supported);
 	}
 
+	linkmode_copy(phy->advertising, phy->supported);
+
 	ret = phy_device_register(phy);
 	if (ret) {
 		phy_device_free(phy);