kernel: fix phy aneg crash

Fix a kernel crash caused when CONFIG_FIXED_PHY used for fixed phy drivers
in phy-add-aneg-done-function patch.

Signed-off-by: Tim Harvey <[email protected]>

target/linux/generic/patches-3.18/702-phy_add_aneg_done_function.patch

@@ -19,7 +19,7 @@
  {
  	int status;
  
-+	if (phydev->drv->update_link)
++	if (phydev->drv && phydev->drv->update_link)
 +		return phydev->drv->update_link(phydev);
 +
  	/* Do a fake read */

target/linux/generic/patches-4.4/702-phy_add_aneg_done_function.patch

@@ -19,7 +19,7 @@
  {
  	int status;
  
-+	if (phydev->drv->update_link)
++	if (phydev->drv && phydev->drv->update_link)
 +		return phydev->drv->update_link(phydev);
 +
  	/* Do a fake read */

target/linux/generic/patches-4.9/702-phy_add_aneg_done_function.patch

@@ -19,7 +19,7 @@
  {
  	int status;
  
-+	if (phydev->drv->update_link)
++	if (phydev->drv && phydev->drv->update_link)
 +		return phydev->drv->update_link(phydev);
 +
  	/* Do a fake read */