debug/pe: add IMAGE_FILE_MACHINE_RISCV{32,64,128}

debug/pe: add IMAGE_FILE_MACHINE_RISCV{32,64,128}

https://docs.microsoft.com/en-us/windows/win32/debug/pe-format

Fixes #54251

Change-Id: I024130fd9f55b2f1c0439baacdc56cdbc3315215
Reviewed-on: https://go-review.googlesource.com/c/go/+/421357
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Meng Zhuo <mzh@golangcn.org>