dev,gpu-compute: Use a TranslationGen in DmaVirtDevice.

Use a TranslationGen to iterate over the translations for a region,
rather than using a ChunkGenerator with a fixed page size the device
needs to know.

Change-Id: I5da565232bd5282074ef279ca74e556daeffef70
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/50763
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Matthew Poremba <matthew.poremba@amd.com>

src/gpu-compute/gpu_command_processor.hh

@@ -135,7 +135,7 @@ class GPUCommandProcessor : public DmaVirtDevice
     typedef void (DmaDevice::*DmaFnPtr)(Addr, int, Event*, uint8_t*, Tick);
     void initABI(HSAQueueEntry *task);
     HSAPacketProcessor *hsaPP;
-    void translateOrDie(Addr vaddr, Addr &paddr) override;
+    TranslationGenPtr translate(Addr vaddr, Addr size) override;
 
     /**
      * Perform a DMA read of the read_dispatch_id_field_base_byte_offset