Support alternative way to use DMA to send display lists to the GPU

[AntonioND]

Right now the only ways supported by Nitro Engine to send display lists to the GPU are to use the CPU itself to copy the display list, or to use the DMA in GFX FIFO mode. This DMA mode is buggy and it can't be used at the same time as the HBL DMA mode, so this task involves creating a new way to send the display lists using DMA.

The new way should setup an interrupt to trigger when the GFX FIFO is half empty, or empty, and it should use DMA to send more commands to the FIFO.