arch-gcn3: Delete extraneous registers header

This file is a duplicate of arch/amdgpu/gcn3/gpu_registers.hh and is in
the wrong location. It should be removed to avoid mistakenly editing the
wrong file.

Change-Id: Ie96e22fe8f78fda954af788b472ec2df4782e4a5
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53743
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
1 file changed