Add CPUARM_HAS_UMULL flag

Pre armv4 and all *M variants to not support UMULL and SMULL.

The Flag now gets used for 32x32->64 and 64x64->64 optimized code.

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@26354 3ad0048d-3df7-0310-abae-a5850022a9f2