phy: sun4i-usb: add support for missing USB PHY index

The new Allwinner H6 SoC's USB2 PHY has two holes -- USB1 (which is a
3.0 port with dedicated PHY) and USB2 (which doesn't exist at all).

Add support for this kind of missing USB PHY index.

Signed-off-by: Icenowy Zheng <[e-mail]>
Reviewed-by: Chen-Yu Tsai <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

drivers/phy/allwinner/phy-sun4i-usb.c

···
 	bool dedicated_clocks;
 	bool enable_pmu_unk1;
 	bool phy0_dual_route;
+	int missing_phys;
 };
 
 struct sun4i_usb_phy_data {
···
 	if (args->args[0] >= data->cfg->num_phys)
 		return ERR_PTR(-ENODEV);
 
+	if (data->cfg->missing_phys & BIT(args->args[0]))
+		return ERR_PTR(-ENODEV);
+
 	return data->phys[args->args[0]].phy;
 }
 
···
 	for (i = 0; i < data->cfg->num_phys; i++) {
 		struct sun4i_usb_phy *phy = data->phys + i;
 		char name[16];
+
+		if (data->cfg->missing_phys & BIT(i))
+			continue;
 
 		snprintf(name, sizeof(name), "usb%d_vbus", i);
 		phy->vbus = devm_regulator_get_optional(dev, name);