Don't use extra EDID resolution when it's 640x480

[axeld]

Older monitors obviously don't use the "additional video mode" to define their native/best/preferred resolution. Instead, you'll obviously often find something like 640x480 there. See #4625 for an example syslog.

This could be detected, and a better mode be chosen if EDID allows it.

I filed this under the app_server, but this also affects the boot loader.

[ttcoder]

I'll report for sure if it turns out that the fix for this ticket allows to also close the infamous "Hyundai" ticket I've filed :-)