GameINI: Replace Wii.Widescreen with AspectRatio

Wii.Widescreen is a setting that cannot be changed on the fly after
emulation has started, so anything booted after the initial title
will have an unexpected aspect ratio.

We can just set Video_Settings.AspectRatio instead, which *can* be live
changed, since it doesn't involve messing with the SYSCONF at any time.

This is also much closer to the behaviour of the Wii U, which
configures the DMCU to force 4:3 transparently, instead of doing it the
intrusive way (touching the SYSCONF).

Data/Sys/GameSettings/RGM.ini

@@ -17,5 +17,5 @@ EmulationIssues =
 [ActionReplay]
 # Add action replay cheats here.
 
-[Wii]
-Widescreen = False
+[Video_Settings]
+AspectRatio = 2