QPointer: mark the dereference operator noexcept, too

The std types do that on their smart pointer types, so while it's not
100% correct (the function has the precondition !isNull()), follow
upstream and mark this operator noexcept, too.

Change-Id: Ie688598215afe2db4c0c26fcfa192fc7c8e22150
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

src/corelib/kernel/qpointer.h

@@ -73,7 +73,7 @@ public:
     { return data(); }
     T* operator->() const noexcept
     { return data(); }
-    inline T& operator*() const
+    T& operator*() const noexcept
     { return *data(); }
     operator T*() const noexcept
     { return data(); }