Add Crop Overscan option for proper NTSC 480i/p CRT output

[forkymcforkface]

This PR Adds a new core option to fix NTSC video output for CRT displays by cropping the 528-line EFB to standard 480i/p resolution.

I'm not 100% set on the option name as this could also be used on LCD displays for those that want to throw away the junk pixels

Problem
GameCube/Wii uses a 640x528 framebuffer internally, but NTSC video output is 640x480.

When the core reports 528 lines to frontends a few problems arise.

• CRTSwitchres calculates and creates incorrect video timings, causing ~55Hz output instead of correct ~60Hz
• Audio stuttering since the game is running too slow to sync
• Not true to the original output seen on NGC/Wii with CRT Displays

Solution
New core option: Graphics > Settings > Crop Overscan (default: disabled)

When enabled for NTSC games:

• Reports 640x480 geometry to frontend (ensures correct 60Hz timing)
• Forces g_Config.bCrop = true (crops EFB internally, prevents squishing)
• Updates video backend surface/swapchain creation to match
• PAL games are unaffected - all changes are NTSC-conditional.
• Supports scaled internal resolutions (2x = 960p, 3x = 1440p etc)
• Uses Dolphin's existing crop mechanism for proper aspect ratio

Testing

• NTSC: Verify 640x480@60Hz output, no vertical squishing
• PAL: untested unchanged behavior (528/576 lines @50Hz)
• Scaled: verified 2x/3x multiplies 480, not 528

[cscd98]

Looks good, just change the bool to const bool for slight optimization.

Untested.

[forkymcforkface]

Looks good, just change the bool to const bool for slight optimization.

Untested.

Fat fingered a few things, but I'm back now

bool to const bool and synced with the latest.