newbus: Optimize/Simplify kobj_class_compile_common a little

"i" is not used in this loop at all. There's no need to initialize and
increment it.

Reviewed by:		markj@
Sponsored by:		Netflix
Differential Revision:	https://reviews.freebsd.org/D29898

sys/kern/subr_kobj.c

@@ -112,7 +112,7 @@ kobj_class_compile_common(kobj_class_t cls, kobj_ops_t ops)
 	/*
 	 * First register any methods which need it.
 	 */
-	for (i = 0, m = cls->methods; m->desc; i++, m++) {
+	for (m = cls->methods; m->desc; m++) {
 		if (m->desc->id == 0)
 			m->desc->id = kobj_next_id++;
 	}