phy: fix kernel oops in phy_lookup()

The kernel oopses in phy_lookup() due to 'phy->init_data' being NULL if we
register PHYs from a device tree probing driver and then call phy_get() on a
device that has no representation in the device tree (e.g. a PCI device).
Checking the pointer before dereferening it and skipping an interation if
it's NULL prevents this kernel oops.
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/phy/phy-core.c

@@ -64,6 +64,9 @@ static struct phy *phy_lookup(struct device *device, const char *port)
 	class_dev_iter_init(&iter, phy_class, NULL, NULL);
 	while ((dev = class_dev_iter_next(&iter))) {
 		phy = to_phy(dev);
+
+		if (!phy->init_data)
+			continue;
 		count = phy->init_data->num_consumers;
 		consumers = phy->init_data->consumers;
 		while (count--) {