Revert "GPU: Go to 533 Mhz fix up the incorrect pll references for Mhz calculation: pushistiky"

This reverts commit 379cac67fa8c71b10bc524ef4b3a5e271481e7c5.
Revert "Try some GPU OC and see what happens"

This reverts commit fe316cc0fde58c63803b7854b6ce99fe921f9eb3.
GPU: OC: A nice little way to modify pll15_config.l on the fly to provide OC steps of 504, 544 and 600.  Still trying to find a way to reflect tha actual max_gpuclk, all commented code still wont allow it, will look at agin at a later date