Fix broken UART console output on RK356x in ACPI mode

[s199p.wa1k9r_gmail.com]

Summary

This patch fixes garbage output to the UART console after running the kernel in ACPI mode

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=271754

Test Plan

Tested on

TianoCore EDK2 UEFI from Jared McNeill
https://github.com/jaredmcneill/quartz64_uefi/releases
on Firefly Station-P2 (ROC-RK3568-PC RK3568)
and on MOCHAbin (Marvell Armada 88F7040)
https://globalscaletechnologies.com/product/mochabin-copy/

[imp]

So why does this fix things? Otherwise, looks like it's OK

[s199p.wa1k9r_gmail.com]

In D40407#920099, @imp wrote:

So why does this fix things? Otherwise, looks like it's OK

This is a very difficult question for me.
Especially if you look at the content.

contrib/dev/acpica/include/acpi.h

I myself would like to receive an answer to it.
It's very hard to debug when you don't have a console.
I'm just trying to offer a solution. And it works.

I understand that the members of the FreeBSD community
have few hardware on RK356x, and there are very few people who are interested
in fixing this error (everyone is used to using u-boot for Rockchip). But using TianoCore EDK2 UEFI
makes it easy to run FreeBSD on new hardware (just having a UEFI BootLoader is enough).
If you need additional information in order to find the cause of the error,
I am ready to provide it later.