gpu-compute: Don't use emulated driver in full system

The emulated driver is currently called in a few locations
unconditionally. This changeset adds checks that we are not in full
system before calling any emulated driver function. In full system the
amdgpu driver running on the disk image handles these functions.

Change-Id: Iea3546b574e29c649351c0fce9154530be89e9b1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/57712
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/gpu-compute/gpu_compute_driver.cc

@@ -1023,6 +1023,7 @@ GPUComputeDriver::setMtype(RequestPtr req)
 {
     // If we are a dGPU then set the MTYPE from our VMAs.
     if (isdGPU) {
+        assert(!FullSystem);
         AddrRange range = RangeSize(req->getVaddr(), req->getSize());
         auto vma = gpuVmas.contains(range);
         assert(vma != gpuVmas.end());