net: phy: c45: fix network interface initialization failures on xtensa, arm:cubieboard

Without proper initialization, "changed" returned random numbers and caused
interface initialization failures.

Fixes: 022c3f87 ("net: phy: add genphy_c45_ethtool_get/set_eee() support")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230225071644.2754893-1-o.rempel@pengutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/phy-c45.c

@@ -672,7 +672,7 @@ EXPORT_SYMBOL_GPL(genphy_c45_read_mdix);
  */
 int genphy_c45_write_eee_adv(struct phy_device *phydev, unsigned long *adv)
 {
-	int val, changed;
+	int val, changed = 0;
 
 	if (linkmode_intersects(phydev->supported_eee, PHY_EEE_CAP1_FEATURES)) {
 		val = linkmode_to_mii_eee_cap1_t(adv);