`ulong` may not be sufficiently wide for addresses returned by the DMA
API. For example, a 32-bit platform can still have DMA addresses larger
than 32-bit. By using the correct type `dma_addr_t` we fix this
truncation.
Change-Id: Ibdf6456fdf12d889296e580de2acb910527ce0aa
Signed-off-by: Waqar Hameed <waqarh@axis.com>