Improper GnGeo Scaling for MMv4 Display

[allanrps]

Checklist

• I am reporting a bug in the Onion OS - Any issues with the closed source frontend (MainUI), or RetroArch or any of the cores should be directed to their respective repositories
• I have reviewed the Onion Docs and did not find the answer
• I have searched the existing (open and closed) issues to ensure I do not log a duplicate

Onions OS Version

4.3.0

Miyoo Firmware Version

202407211632

Provide a clear and concise description of the issue

The display output for the current implementation of the GnGeo standalone core scales the output to 640x480, presenting an offset and poorly rendered image when viewed on the Miyoo Mini v4's 750x560 display.

Steps to Reproduce

Run any game in the GnGeo core and observe the scaling.

Provide any additional context or information that may help us investigate your issue

A 4:3 full screen stretched 750x560 output is the best looking scaled output for Neo-Geo on the v4, and that should be the default option.