Report ROM loading progress in debug output

[misteraddons]

Prints ROM loading progress in 10% increments to debug
Useful for debugging rom load speed and for external devices to display loading progress

Loading ROM   0% (0 ms)
Loading ROM  10% (135 ms)
Loading ROM  20% (268 ms)
Loading ROM  30% (399 ms)
Loading ROM  40% (533 ms)
Loading ROM  50% (666 ms)
Loading ROM  60% (801 ms)
Loading ROM  70% (933 ms)
Loading ROM  80% (1066 ms)
Loading ROM  90% (1199 ms)
Loading ROM 100% (1332 ms)
file_finish: 0x200000 bytes sent to FPGA

Ignores BIOS file and optical disc loading
Special handling of N64, Neo-Geo and .mra
Guarded by MiSTer.ini debug=1 - no new MiSTer.ini settings

Tested and working:

• Arcade MGL
• Neo-Geo
• Atari 7800
• Atari Lynx
• NES
• SNES
• N64
• Game Boy
• GBA
• SMS
• MegaDrive
• 32X
• TurboGrafx-16
• Jaguar
• Vectrex

Tested and intentionally untouched:

• CDi
• MegaCD
• PSX
• Saturn