This  corrects the implementation of Thumb ADR instruction. There are three issues:
1. it should accept only 4-byte aligned addresses
2. the maximum offset should be 1020
3. it should be encoded with the offset scaled by two bits


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185528 91177308-0d34-0410-b5e6-96231b3b80d8