net: phylink: fix failure to register on x86 systems

The kernel test robot reports a boot failure with qemu in 5.5-rc,
referencing commit 2203cbf ("net: sfp: move fwnode parsing into
sfp-bus layer"). This is caused by phylink_create() being passed a
NULL fwnode, causing fwnode_property_get_reference_args() to return
-EINVAL.

Don't attempt to attach to a SFP bus if we have no fwnode, which
avoids this issue.

Reported-by: kernel test robot <[email protected]>
Fixes: 2203cbf ("net: sfp: move fwnode parsing into sfp-bus layer")
Signed-off-by: Russell King <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Reviewed-by: Andrew Lunn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Russell King

drivers/net/phy/phylink.c

@@ -566,6 +566,9 @@ static int phylink_register_sfp(struct phylink *pl,
 	struct sfp_bus *bus;
 	int ret;
 
+	if (!fwnode)
+		return 0;
+
 	bus = sfp_bus_find_fwnode(fwnode);
 	if (IS_ERR(bus)) {
 		ret = PTR_ERR(bus);