arch-vega, dev-amdgpu: Fix for memory leaks (#129)

When using the new operator, delete should be called
on any allocated memory after it's use is complete.

Change-Id: Id5fcfb264b6ddc252c0a9dcafc2d3b020f7b5019

src/arch/amdgpu/vega/pagetable_walker.cc

@@ -369,6 +369,7 @@ bool Walker::sendTiming(WalkerState* sending_walker, PacketPtr pkt)
         return true;
     } else {
         (void)pkt->popSenderState();
+        delete walker_state;
     }
 
     return false;

src/dev/amdgpu/amdgpu_device.cc

@@ -291,6 +291,7 @@ AMDGPUDevice::readFrame(PacketPtr pkt, Addr offset)
     system->getDeviceMemory(readPkt)->access(readPkt);
 
     pkt->setUintX(readPkt->getUintX(ByteOrder::little), ByteOrder::little);
+    delete readPkt;
 }
 
 void