hg: panama/dev: Fix build failure on aarch64

[vladimir.x.ivanov at oracle.com]

Changeset: 656a63bca211
Author:    vlivanov
Date:      2020-04-02 20:37 +0300
URL:       https://hg.openjdk.java.net/panama/dev/rev/656a63bca211

Fix build failure on aarch64

! src/hotspot/cpu/aarch64/aarch64.ad