Getting to the bottom of the Dreamcast DMA issue

[Adrian M. <ad...@ne...>]

It appears it is not the sh_dmac code which is to blame, but the
pvr2_dma code. If I fix the build to exclude pvr2_dma.c, the Dreamcast
will boot with CONFIG_NR_ONCHIP_DMA_CHANNELS set correctly (ie to 4)

Plainly the pvr code is broken when it tries to take channel 4, not sure
why though, will have a deeper look.

Adrian