git: openjdk/jdk-sandbox: riscv-port-branch: add comments on globalDefinitions_gcc.hpp

[duke]

Changeset: 93e274e2
Author:    zhuyanhong <zhuyanhong2 at huawei.com>
Date:      2021-10-18 17:41:59 +0000
URL:       https://git.openjdk.java.net/jdk-sandbox/commit/93e274e22ef896da9b160b53d55822e1db0b8a37

add comments on globalDefinitions_gcc.hpp

! src/hotspot/share/utilities/globalDefinitions_gcc.hpp