base,arch-hsail: Fix GPU build

base,arch-hsail: Fix GPU build

The GPU build is currently broken due to recent changes. This fixes
the build after changes to local access, removal of getSyscallArg,
and creating of AMO header in base.

Change-Id: I43506f6fb0a92a61a50ecb9efa7ee279ecb21d98
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27136
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Bradford Beckmann <brad.beckmann@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
Tested-by: Gem5 Cloud Project GCB service account <345032938727@cloudbuild.gserviceaccount.com>