This patch adds intrinsics for the following MVE instructions:
- VABAV
- VMLADAV, VMLSDAV
- VMLALDAV, VMLSLDAV
- VRMLALDAVH, VRMLSLDAVH
Each of the above 4 groups has a corresponding new LLVM IR intrinsic,
since the instructions cannot be easily represented using
general-purpose IR operations.
Types again?