Fix: Address a few benign memory leaks

This patch is the result of static analysis identifying a number of
memory leaks. The leaks are all benign as they are a result of not
deallocating memory in the desctructor. The fix still has value as it
removes false positives in the static analysis.

src/dev/arm/pl111.cc

@@ -84,6 +84,11 @@ Pl111::Pl111(const Params *p)
         vncserver->setFramebufferAddr(dmaBuffer);
 }
 
+Pl111::~Pl111()
+{
+    delete[] dmaBuffer;
+}
+
 // read registers and frame buffer
 Tick
 Pl111::read(PacketPtr pkt)

src/dev/arm/pl111.hh

@@ -316,6 +316,7 @@ class Pl111: public AmbaDmaDevice
         return dynamic_cast<const Params *>(_params);
     }
     Pl111(const Params *p);
+    ~Pl111();
 
     virtual Tick read(PacketPtr pkt);
     virtual Tick write(PacketPtr pkt);