gpu: host1x: debug: Use dma_addr_t more consistently

The host1x debug code uses a mix of phys_addr_t, dma_addr_t and u32 to
represent addresses. However, these addresses are always DMA addresses
so use the appropriate type.

This fixes some issues with how these addresses are displayed, because
they could be truncated in some cases and not show the full address.

Signed-off-by: Thierry Reding <treding@nvidia.com>