dev-amdgpu: Add missing 'overrides'

This causes warnings/errors in some compilers.

Change-Id: I36a3548943c030d2578c2f581c8985c12eaeb0ae

src/arch/amdgpu/vega/insts/instructions.hh

diff --git a/src/arch/amdgpu/vega/insts/instructions.hh b/src/arch/amdgpu/vega/insts/instructions.hh
index d45a84c..0e4ec04 100644
--- a/src/arch/amdgpu/vega/insts/instructions.hh
+++ b/src/arch/amdgpu/vega/insts/instructions.hh
@@ -31534,8 +31534,8 @@
         } // getOperandSize
 
         void execute(GPUDynInstPtr) override;
-        void initiateAcc(GPUDynInstPtr gpuDynInst);
-        void completeAcc(GPUDynInstPtr gpuDynInst);
+        void initiateAcc(GPUDynInstPtr gpuDynInst) override;
+        void completeAcc(GPUDynInstPtr gpuDynInst) override;
     }; // Inst_DS__DS_OR_B32
 
     class Inst_DS__DS_XOR_B32 : public Inst_DS