Thumb2 assembly parsing and encoding for STR.

More addressing mode encoding bits. Handle pre increment for STR/STRB/STRH
and STR(register).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139949 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed