usb: dwc3: fix a test for error in dwc3_core_init()

This was refactored recently and the "ret = " was accidentally deleted
so the errors aren't checked.

Fixes: 1d72fab4 ("USB: dwc3: refactor phy handling")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/d0c5a04f-deee-4ebe-9b0b-dc5492564519@kili.mountainSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/core.c

@@ -1137,7 +1137,7 @@ static int dwc3_core_init(struct dwc3 *dwc)
 
 	dwc3_set_incr_burst_type(dwc);
 
-	dwc3_phy_power_on(dwc);
+	ret = dwc3_phy_power_on(dwc);
 	if (ret)
 		goto err_exit_phy;