qatomiccomparatorlocators.cpp: Fix signedness comparison warnings

Fix numerous warnings:
qtxmlpatterns/src/xmlpatterns/type/qatomiccomparatorlocators.cpp:61:57: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
     if(((validOps) & AtomicComparator::Operator(op)) == op)

Task-number: QTBUG-58173
Change-Id: Ic256d51e9a3306b960afecf8eb7b48e451c89144
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>