Avoid signed/unsigned warning in template

tst_QtEndian's transformRegion_template() was getting a
signed/unsigned comparison warning when T was unsigned in a
QCOMPARE(T-value, 0); so use T(0) instead.

Change-Id: I78cb2ab96f79393def65ed2c020aa3039017ab92
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

tests/auto/corelib/global/qtendian/tst_qtendian.cpp

@@ -134,7 +134,7 @@ void transformRegion_template(T (*transformOne)(T), void (*transformRegion)(cons
 
     auto checkBounds = [&](int from) {
         for ( ; from < Size; ++from)
-            QCOMPARE(dest[from], 0);
+            QCOMPARE(dest[from], T(0));
     };
 
     transformRegion(source, 1, dest);