phy: stm32: fix an error code in probe

If "index > usbphyc->nphys" is true then this returns success but it
should return -EINVAL.

Fixes: 94c358da ("phy: stm32: add support for STM32 USB PHY Controller (USBPHYC)")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/Y0kq8j6S+5nDdMpr@kiliSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/st/phy-stm32-usbphyc.c

@@ -710,6 +710,8 @@ static int stm32_usbphyc_probe(struct platform_device *pdev)
 		ret = of_property_read_u32(child, "reg", &index);
 		if (ret || index > usbphyc->nphys) {
 			dev_err(&phy->dev, "invalid reg property: %d\n", ret);
+			if (!ret)
+				ret = -EINVAL;
 			goto put_child;
 		}