DSP context switch support

From: Mori Hiroki <yamori813_at_yahoo.co.jp>
Date: Wed, 08 Mar 2023 07:25:46 UTC
Hi

I consider DSP support.

This is skeleron code.

https://github.com/ZRouter/freebsd-src/commit/483b3b7a5d871ca7c0cf3b5c03e9543559376f60

If you have advice, please let me know.

Thanks

Hiroki Mori