second uart at AR934X

From: Mori Hiroki <yamori813_at_yahoo.co.jp>
Date: Tue, 30 Dec 2025 01:20:17 UTC
Hi

I add high speed uart support for AR934X.

https://github.com/ZRouter/freebsd-src/commit/a6c5320608a766dd513679066dbad23c28b9133a

Thanks

Hiroki Mori