(MESS) gamegear: moved GG-SMS scaling from VDP file to the machine file;
undone the specific X-Scroll timing introduced to fix Chicago Syndicate, for Game
Gear, because it causes problems with the games Sonic Drift 1 and 2; reduced
the amount of duplicated code in the VDP file. [Enik Land]

out of whatsnew: gamegear units modded to output the image signal to a TV are able
to show games using SMS compatibility mode in full screen, without scaling, while
native GG games are displayed in a centered, smaller image, that is surrounded by
bigger borders. Also, GG units that have the original LCD display replaced by another
LCD display model (not just the back-light) also displays SMS compatibility games
without scaling, and native games with borders. This suggests that the scaling
isn't performed by the VDP and therefore motivated the moving of the scaling code
in this commit.