sysfs: sysfs_create_groups returns a value.

When I included the "empty" function for sysfs_create_groups() when
CONFIG_SYSFS=n, I forgot to return a value for it, so things blew up the
build.  This patch fixes that, stupid me.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/sysfs.h

@@ -353,6 +353,7 @@ static inline int sysfs_create_group(struct kobject *kobj,
 static inline int sysfs_create_groups(struct kobject *kobj,
 				      const struct attribute_group **groups)
 {
+	return 0;
 }
 
 static inline int sysfs_update_group(struct kobject *kobj,