gpu-compute: Add operand info class to GPUDynInst

This change adds a class that stores operand register info
for the GPUDynInst. The operand info is calculated when the
instruction object is created and stored for easy access
by the RF, etc.

Change-Id: I3cf267942e54fe60fcb4224d3b88da08a1a0226e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/42209
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>

src/gpu-compute/SConscript

@@ -80,6 +80,7 @@ DebugFlag('GPUInitAbi')
 DebugFlag('GPUDisp')
 DebugFlag('GPUExec')
 DebugFlag('GPUFetch')
+DebugFlag('GPUInst')
 DebugFlag('GPUKernelInfo')
 DebugFlag('GPUMem')
 DebugFlag('GPUPort')