Fix memory allocation error in Port::memsetBlobFunctional.

mem/port.cc:
    Delete temp buffer for memset.

--HG--
extra : convert_revision : d7e2868c173442ca904898633f7ea9fc5e612dd3

mem/port.cc

@@ -71,4 +71,6 @@ Port::memsetBlobFunctional(Addr addr, uint8_t val, int size)
 
     memset(buf, val, size);
     blobHelper(addr, buf, size, Write);
+
+    delete buf;
 }