PPS: convert class code to use dev_groups

The dev_attrs field of struct class is going away soon, dev_groups
should be used instead.  This converts the pps class code to use the
correct field.

Cc: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
index 7db3eb9..1d2cd21 100644
--- a/include/linux/pps_kernel.h
+++ b/include/linux/pps_kernel.h
@@ -80,7 +80,7 @@
  * Global variables
  */
 
-extern struct device_attribute pps_attrs[];
+extern const struct attribute_group *pps_groups[];
 
 /*
  * Internal functions.