Bug:Baud rate cannot be fixed

[micas-net]

Is it platform specific

generic

Importance or Severity

High

Description of the bug

The following PR ，can specify a fixed baud rate setting:
#1734
#8595

However, the systemd version is updated, and the content of [email protected] is also changing. The following PR updates the command for setting the baud rate by removing the parameter %I after /sbin/agetty. As a result, the program_console_speed function in rc.local cannot match this command line, and the fixed baud rate function cannot be implemented.
systemd/systemd#21171

In this way, the baud rate will keep changing when the serial port logs out/in multiple times。

Steps to Reproduce

Multiple logout/login of serial port

Actual Behavior and Expected Behavior

Actual Behavior：The serial port continuously logs in/out, and the baud rate is selected from 115200, 57600, 38400, 9600 each time, and cannot be fixed

Expected Behavior：the console baudrate is fixed to a specific one after boot up.

[micas-net]

This issue fixes by #22458