device: Fix comment for driver_data in struct device

dev_set_drvdata/dev_get_drvdata is used to access driver_data
in struct device.
Signed-off-by: David Engraf <david.engraf@sysgo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/device.h

@@ -988,7 +988,7 @@ struct device {
 	void		*platform_data;	/* Platform specific data, device
 					   core doesn't touch it */
 	void		*driver_data;	/* Driver data, set and get with
-					   dev_set/get_drvdata */
+					   dev_set_drvdata/dev_get_drvdata */
 	struct dev_links_info	links;
 	struct dev_pm_info	power;
 	struct dev_pm_domain	*pm_domain;