as: Add new atomic instructions in LoongArch v1.1

LoongArch V1.1 release is out at
https://github.com/loongson/LoongArch-Documentation.

New atomic instructions in LoongArch v1.1:

- sc.q
- llacq.w/d
- screl.w/d
- amcas{_db}.b/h/w/d
- amswap{_db}.b/h
- amadd{_db}.b/h

Signed-off-by: Jiajie Chen <c@jia.je>
4 files changed