Fix VLDMQ and VSTMQ instructions to use the correct encoding and address modes.

Fix VLDMQ and VSTMQ instructions to use the correct encoding and address modes.
These instructions are only needed for codegen, so I've removed all the
explicit encoding bits for now; they should be set in the same way as the for
VLDMD and VSTMD whenever we add encodings for VFP.  The use of addrmode5
requires that the instructions be custom-selected so that the number of
registers can be set in the AM5Opc value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99309 91177308-0d34-0410-b5e6-96231b3b80d8