Remove execute_cycles adjustment based on video_count value

[andymcca]

Commenting out this line appears to fix issue #224 with no adverse effects elsewhere, as far as I can see through limited testing on these games and other games in my collection.

@davidgfnet you will know far better than me, but maybe this line is rendered unnecessary following after you implemented DMA sleep mode and taking into account those cycles?

[andymcca]

Ahhh nope, no good. All this does is stops execute cycles syncing with video_count (or zero, if video_count is negative), so it puts the timing out of whack. It DOES clear up the visuals on all the games in the issue, but it introduces a big speed penalty on the emulator, so not a 'no effect' change and need to understand what the actual issue is otherwise shooting in the dark. Closing.....