driver core: let dev_set_drvdata return int instead of void as it can fail

Before commit

	b402843 (Driver core: move dev_get/set_drvdata to drivers/base/dd.c)

calling dev_set_drvdata with dev=NULL was an unchecked error. After some
discussion about what to return in this case removing the check (and so
producing a null pointer exception) seems fine.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/include/linux/device.h b/include/linux/device.h
index 350ceda..2215d01 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -557,7 +557,7 @@
 extern const char *device_get_devnode(struct device *dev,
 				      mode_t *mode, const char **tmp);
 extern void *dev_get_drvdata(const struct device *dev);
-extern void dev_set_drvdata(struct device *dev, void *data);
+extern int dev_set_drvdata(struct device *dev, void *data);
 
 /*
  * Root device objects for grouping under /sys/devices