QHash: remove unnecessary #ifdef

There's no need to use a macro here, since we can just store
the pointer value in a qulonglong and have the second shift
operation be done unconditionally. For 32-bit platforms, it
will yield 0, and xor'ing it into 'seed' will have no effect.

Change-Id: I3e63bd504e81c84d13935d5503c3707d40d74d6f
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/tools/qhash.cpp

@@ -267,9 +267,7 @@ static uint qt_create_qhash_seed()
 
     quintptr seedPtr = reinterpret_cast<quintptr>(&seed);
     seed ^= seedPtr;
-#if QT_POINTER_SIZE == 8
-    seed ^= (seedPtr >> 32);
-#endif
+    seed ^= (qulonglong(seedPtr) >> 32); // no-op on 32-bit platforms
 #endif // QT_BOOTSTRAPPED
 
     return seed;