[clang] [RISCV] Update Zicntr and Zihpm to version 2p0 (PR #66323)

[Jianjian Guan via cfe-commits]

jacquesguan wrote:

> Sorry, that was a mis-statement. There are two counter extensions you are bumping.
> 
> Anyway, rewording the commit message is a nit from me.

OK, I retitle the commit.

https://github.com/llvm/llvm-project/pull/66323