Revert "Do not wait for the DMA to be done before drawing the screen. This requires that ds2_flipScreen works from top to bottom and that DMA completes faster than ds2_flipScreen."

This reverts commit bdb82830ded1e87c21a6c551f4170888f4296584.
Revert "Wait for DMA to be finished before downclocking the CPU for the main menu."

This reverts commit 6d3e4b69b425db2cb8ffc8ea57166949cb4df074.