use optimized cg loading functions in 64bit compares instead of hardcoded move.ls (move.l #X,dn is 48bit long, clr.l/moveq.l is 16bit long)

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26570 3ad0048d-3df7-0310-abae-a5850022a9f2