[clang] [llvm] [RISCV] Inline Assembly: RVC constraint and N modifier (PR #112561)

[Pengcheng Wang via cfe-commits]

https://github.com/wangpc-pp approved this pull request.

LGTM.
I like this change and adding support of paired registers is on my todo list as well.

https://github.com/llvm/llvm-project/pull/112561