drbd: Convert resync-after into a signed netlink field

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/include/linux/genl_magic_func.h b/include/linux/genl_magic_func.h
index e908f1c..94e839a 100644
--- a/include/linux/genl_magic_func.h
+++ b/include/linux/genl_magic_func.h
@@ -437,6 +437,9 @@
 #undef __u32_field_def
 #define __u32_field_def(attr_nr, attr_flag, name, default)		\
 	x->name = default;
+#undef __s32_field_def
+#define __s32_field_def(attr_nr, attr_flag, name, default)		\
+	x->name = default;
 #undef __flg_field_def
 #define __flg_field_def(attr_nr, attr_flag, name, default)		\
 	x->name = default;