driver core: make device_{add|remove}_groups() public

Many drivers create additional driver-specific device attributes when
binding to the device. To avoid them calling SYSFS API directly, let's
export these helpers.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/device.h b/include/linux/device.h
index 9ef518a..10cf209 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1200,6 +1200,11 @@
 			     const char *fmt, ...);
 extern void device_destroy(struct class *cls, dev_t devt);
 
+extern int __must_check device_add_groups(struct device *dev,
+					const struct attribute_group **groups);
+extern void device_remove_groups(struct device *dev,
+				 const struct attribute_group **groups);
+
 /*
  * Platform "fixup" functions - allow the platform to have their say
  * about devices and actions that the general device layer doesn't