backlight: pwm: Handle EPROBE_DEFER while requesting the PWM

When trying to request the PWM device with devm_pwm_get(), the EPROBE_DEFER
flag is not handled properly. It can lead to the PWM not being found.
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/video/backlight/pwm_bl.c

@@ -274,6 +274,10 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 
 	pb->pwm = devm_pwm_get(&pdev->dev, NULL);
 	if (IS_ERR(pb->pwm)) {
+		ret = PTR_ERR(pb->pwm);
+		if (ret == -EPROBE_DEFER)
+			goto err_alloc;
+
 		dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n");
 		pb->legacy = true;
 		pb->pwm = pwm_request(data->pwm_id, "pwm-backlight");