Thumb2 ADD/SUB instructions encoding selection outside IT block.

Thumb2 ADD/SUB instructions encoding selection outside IT block.

Outside an IT block, "add r3, #2" should select a 32-bit wide encoding
rather than generating an error indicating the 16-bit encoding is only
legal in an IT block (outside, the 'S' suffic is required for the 16-bit
encoding).

rdar://10348481

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143201 91177308-0d34-0410-b5e6-96231b3b80d8