Driver uses dma_alloc_coherent to allocate dma memory for descriptors,
dma_alloc_coherent will return both the virtual address and physical
address. AFAIK, virt_to_phys could not convert virtual address to
physical address, for which memory is allocated by dma_alloc_coherent.

dwmac4_display_ring() function is broken for various descriptor, it only
support normal descriptor(struct dma_desc) now, this patch also extends to
support all descriptor types.
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>