dma: pl330: use dma_addr_t for describing bus addresses

The microcode bus address (pl330_dmac.mcode_bus) is currently a u32,
which fails to compile when building on a system with 64-bit bus
addresses.

This patch uses dma_addr_t to represent the address instead.

Cc: Jassi Brar <jaswinder.singh@linaro.org>
Cc: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Jassi Brar <jaswinder.singh@linaro.org>
Acked-by: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>