Simplemining just implemented Rxboost on linux

It's rather simple adjustment that I discovered a few days ago, so it's easy to clone it

It works for old AMD cards too, so "-rxboost" option will also support old cards in next update.
The real magic is to apply straps on latest Nvidia (Turing), Nvidia protected these cards from such tricks, I have a solution for it too, but need some time to implement it properly before including into miner.