dev-amdgpu: Remove cached copy of device memory

This map was originally used for fast access to the GART table. It is no
longer needed as the table has been moved to the AMDGPUVM class. Along
with commit 12ec5f9172301a121a949c622a03a839b0e45d4e which reads
functionally from device memory, this table is no longer needed and is
essentially a duplicate copy of device memory for anything written over
the PCI BAR.

This changeset removes the map entirely which will reduce the memory
footprint of simulations and potentially avoid stale copies of data
when reading over the PCI BAR.

Change-Id: I312ae38f869c6a65e50577b1c33dd055078aaf32
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/63951
Reviewed-by: Matt Sinclair <mattdsinclair.wisc@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
2 files changed