[llvm] [RISCV] Update counters to version 2p0 (PR #66323)

[Yueh-Ting Chen via llvm-commits]

eopXD 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.

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