pwm: bcm2835: Support for polarity setting via DT

This adds support for the third (optional) pwm cell to specify the
polarity, which is needed by display backlights for example.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-bcm2835.c

@@ -167,6 +167,8 @@ static int bcm2835_pwm_probe(struct platform_device *pdev)
 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &bcm2835_pwm_ops;
 	pc->chip.npwm = 2;
+	pc->chip.of_xlate = of_pwm_xlate_with_flags;
+	pc->chip.of_pwm_n_cells = 3;
 
 	platform_set_drvdata(pdev, pc);