Use const instead of a comment.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2946 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Handle fcvtpu Xd,Sn.  Fixes #335564.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2947 8f6e269a-dfd6-0310-a8e1-e2731360e62c