[clang] [llvm] [RISCV] Mark {vl, vtype} as clobber in inline assembly (PR #128636)

[Pengcheng Wang via cfe-commits]

wangpc-pp wrote:

I am not familiar with the target attribute implementation, can we get the list of function features here and add the clobbers at: https://github.com/llvm/llvm-project/blob/6d93280aabc2fd132f54e5aa615d25abeadabe7b/clang/lib/CodeGen/CGStmt.cpp#L3087-L3093
cc @topperc @4vtomat 

https://github.com/llvm/llvm-project/pull/128636