Feature request: Add 230400 baud to PPP menu

[thera34]

Hi,

For quite some time, me and others are using successfully a "hack" of the uartmode script to achieve 230400 baud PPP connection on Minimig, basically doubling the normal 115200 baud connection. It proved to be stable and no issues were encountered afaik.
Unfortunately that method is not much convenient, might get erased on updates etc.
A more elegant solution would be to simply add the new speed in the Minimig.sv:

localparam CONF_STR = {
	"Minimig;UART115200:230400,MIDI;",

This way, the uartmode script will pick up and use the PPP speed value directly, without the need of previous "hacky method"
Of course, the PPP client on Amiga side (I tested MiamiDX without any issues) must be set to the new speed value.

Benefits:
Well, double the speed when using PPP, especially useful while using imp3 (Amiga modules internet radio), MUIMapparium (OpenStreetMaps alternative to Gmaps for Amiga) or simple FTP transfers etc

Notes:
I've been using this speed for years and didn't encountered any issues, and as mentioned other people as well (especially BinaryBond007, from which actually I learned about "hacking" the uartmode script for Minimig)
As a side note, we did try to go beyond 230400, but to no avail, so double the speed is nice too :)

Please let me know your thoughts, if needed I can raise a PR as well

Additional Links:
https://discord.com/channels/647909397477195803/1047332497492553799/1305867216658628609
https://misterfpga.org/viewtopic.php?p=92202#p92202
https://mister-devel.github.io/MkDocs_MiSTer/advanced/computer/#cores-supporting-serial-connection

[limi]

Adding my +1 to this, it would be great to have the increased speed, especially now that AmigaVision includes an internet setup by default. It seems stable at 230K.

[sorgelig]

Need to think if there are some cons from this change...

[thera34]

I tried to find myself some cons, but as said before, the core is stable at that speed and didn't encounter any issues, been using it for two months already with this modification (and before 2 years with the uartmode script "hack").