Implement SMMLA{r}, both ARM and Thumb.  n-i-bz.  
(Ben Cheng <bccheng@google.com>)

Also, move ARM encoding of SMMUL{R} to a more sensible place.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2713 8f6e269a-dfd6-0310-a8e1-e2731360e62c