OGL: remove ubo workaround

This was only keeped for some broken mesa versions. Meanwhile most used versions should be fixed for almost a year.
[JITARM] Fixes an issue in the slowmem path that causes grey THP movies, and issues of games not working like Mario Kart being incapable of getting ingame. This was due to me forgetting an instruction.
Merge pull request #31 from Sonicadvance1/slowmemfix

[JITARM] Fixes an issue in the slowmem path that causes grey THP movies,...
Merge pull request #14 from degasus/uboWorkaroundRemove

OGL: Remove non-UBO code path.