[llvm] [Offload] Add support for riscv64 to host plugin (PR #115773)

[Joseph Huber via llvm-commits]

jhuber6 wrote:

Add the triple to https://github.com/llvm/llvm-project/blob/0e3c791916a918cd2d7391ddb633fbe5faa00b86/clang/lib/Frontend/CompilerInvocation.cpp#L4228

https://github.com/llvm/llvm-project/pull/115773