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>
diff --git a/drivers/pwm/pwm-lp3943.c b/drivers/pwm/pwm-lp3943.c
index a40b9c3..2c39b0e 100644
--- a/drivers/pwm/pwm-lp3943.c
+++ b/drivers/pwm/pwm-lp3943.c
@@ -278,6 +278,7 @@
 	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);