pwm: lp3943: Set pwm_chip can_sleep flag

Read/write through I2C can sleep, thus set pwm_chip can_sleep flag.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-lp3943.c

@@ -278,6 +278,7 @@ static int lp3943_pwm_probe(struct platform_device *pdev)
 	lp3943_pwm->chip.dev = &pdev->dev;
 	lp3943_pwm->chip.ops = &lp3943_pwm_ops;
 	lp3943_pwm->chip.npwm = LP3943_NUM_PWMS;
+	lp3943_pwm->chip.can_sleep = true;
 
 	platform_set_drvdata(pdev, lp3943_pwm);