Driver core: Add accessor for device platform data

For consistency with driver data provide a dev_get_platdata() accessor
for reading the platform data from a device.

Signed-off-by: Mark Brown <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/linux/device.h

···
 }
 extern void root_device_unregister(struct device *root);
 
+static inline void *dev_get_platdata(const struct device *dev)
+{
+	return dev->platform_data;
+}
+
 /*
  * Manual binding of a device to driver. See drivers/base/bus.c
  * for information on use.