[AVR]  Optimize 16-bit ANDs with '1'

Summary: Fixes PR 31345

Reviewers: dylanmckay

Subscribers: fhahn, llvm-commits

Differential Revision: https://reviews.llvm.org/D28186

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290778 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed