usb: phy: generic: make vcc regulator optional

phy-generic uses the existance of the property "vcc-supply" to see if a
regulator is optional or not. Use devm_regulator_get_optional() instead
which exists for this purpose. Using devm_regulator_get_optional()
avoids "supply vcc not found, using dummy regulator" messages.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20221012132754.292151-1-s.hauer@pengutronix.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/phy/phy-generic.c

@@ -209,7 +209,7 @@ int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop)
 	int err = 0;
 
 	u32 clk_rate = 0;
-	bool needs_vcc = false, needs_clk = false;
+	bool needs_clk = false;
 
 	if (dev->of_node) {
 		struct device_node *node = dev->of_node;
@@ -217,7 +217,6 @@ int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop)
 		if (of_property_read_u32(node, "clock-frequency", &clk_rate))
 			clk_rate = 0;
 
-		needs_vcc = of_property_read_bool(node, "vcc-supply");
 		needs_clk = of_property_read_bool(node, "clocks");
 	}
 	nop->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
@@ -257,13 +256,10 @@ int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_generic *nop)
 		}
 	}
 
-	nop->vcc = devm_regulator_get(dev, "vcc");
-	if (IS_ERR(nop->vcc)) {
-		dev_dbg(dev, "Error getting vcc regulator: %ld\n",
-					PTR_ERR(nop->vcc));
-		if (needs_vcc)
-			return -EPROBE_DEFER;
-	}
+	nop->vcc = devm_regulator_get_optional(dev, "vcc");
+	if (IS_ERR(nop->vcc) && PTR_ERR(nop->vcc) != -ENODEV)
+		return dev_err_probe(dev, PTR_ERR(nop->vcc),
+				     "could not get vcc regulator\n");
 
 	nop->vbus_draw = devm_regulator_get_exclusive(dev, "vbus");
 	if (PTR_ERR(nop->vbus_draw) == -ENODEV)