create the raddr addressing mode that matches any register and the frame index

create the raddr addressing mode that matches any register and the frame index
use raddr for the ldr instruction. This removes a dummy mov from the assembly output
remove SelectFrameIndex
remove isLoadFromStackSlot
remove isStoreToStackSlot

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29079 91177308-0d34-0410-b5e6-96231b3b80d8