pwm: add devm_pwm_get() and devm_pwm_put()

Add resource managed variants of pwm_get() and pwm_put() for
convenience. Code is largely inspired by the equivalent devm functions
of the regulator framework.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 354764c..40c7643 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -148,6 +148,9 @@
 struct pwm_device *pwm_get(struct device *dev, const char *consumer);
 void pwm_put(struct pwm_device *pwm);
 
+struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer);
+void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
+
 struct pwm_lookup {
 	struct list_head list;
 	const char *provider;