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/drivers/base/core.c b/drivers/base/core.c
index bbecaf9..14f8cf5 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1026,12 +1026,14 @@ int device_add_groups(struct device *dev, const struct attribute_group **groups)
 {
 	return sysfs_create_groups(&dev->kobj, groups);
 }
+EXPORT_SYMBOL_GPL(device_add_groups);
 
 void device_remove_groups(struct device *dev,
 			  const struct attribute_group **groups)
 {
 	sysfs_remove_groups(&dev->kobj, groups);
 }
+EXPORT_SYMBOL_GPL(device_remove_groups);
 
 static int device_add_attrs(struct device *dev)
 {