[llvm] [RISCV] Replace HasStdExtZbcOrZbkc with HasStdExtZbkc. NFC (PR #185790)

[Pengcheng Wang via llvm-commits]

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

LGTM. I think we have already applied this form to Zca/C, Zfhmin/Zfh, etc.

https://github.com/llvm/llvm-project/pull/185790