dev_printk(): constify the `dev' argument

Add const markings to dev_name and dev_driver_string to make it clear that
dev_printk doesn't modify dev.  This is a prerequisite to adding more
const markings to other functions make it clearer, which functions can
modify dev and which can't.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/base/core.c

@@ -53,7 +53,7 @@ static inline int device_is_not_partition(struct device *dev)
  * it is attached to.  If it is not attached to a bus either, an empty
  * string will be returned.
  */
-const char *dev_driver_string(struct device *dev)
+const char *dev_driver_string(const struct device *dev)
 {
 	return dev->driver ? dev->driver->name :
 			(dev->bus ? dev->bus->name :

include/linux/device.h

@@ -406,7 +406,7 @@ struct device {
 /* Get the wakeup routines, which depend on struct device */
 #include <linux/pm_wakeup.h>
 
-static inline const char *dev_name(struct device *dev)
+static inline const char *dev_name(const struct device *dev)
 {
 	/* will be changed into kobject_name(&dev->kobj) in the near future */
 	return dev->bus_id;
@@ -518,7 +518,7 @@ extern void device_shutdown(void);
 extern void sysdev_shutdown(void);
 
 /* debugging and troubleshooting/diagnostic helpers. */
-extern const char *dev_driver_string(struct device *dev);
+extern const char *dev_driver_string(const struct device *dev);
 #define dev_printk(level, dev, format, arg...)	\
 	printk(level "%s %s: " format , dev_driver_string(dev) , \
 	       dev_name(dev) , ## arg)