arm: Factorise code to match immediates.
arm: Factorise code to match immediates.

libfirm/libfirm,killbug2004/libfirm,MatzeB/libfirm,jonashaag/libfirm,MatzeB/libfirm,killbug2004/libfirm,libfirm/libfirm,killbug2004/libfirm,killbug2004/libfirm,MatzeB/libfirm,MatzeB/libfirm,killbug2004/libfirm,jonashaag/libfirm,jonashaag/libfirm,jonashaag/libfirm,killbug2004/libfirm,jonashaag/libfirm,MatzeB/libfirm,killbug2004/libfirm,jonashaag/libfirm,libfirm/libfirm,libfirm/libfirm,MatzeB/libfirm,libfirm/libfirm,jonashaag/libfirm,MatzeB/libfirm