remoteproc: mtk_scp: use dma_addr_t for DMA API

remoteproc: mtk_scp: use dma_addr_t for DMA API

dma_addr_t and phys_addr_t are distinct types and must not be
mixed, as both the values and the size of the type may be
different depending on what the remote device uses.

In this driver the compiler warns when the two types are different:

drivers/remoteproc/mtk_scp.c: In function 'scp_map_memory_region':
drivers/remoteproc/mtk_scp.c:454:9: error: passing argument 3 of 'dma_alloc_coherent' from incompatible pointer type [-Werror=incompatible-pointer-types]
  454 |         &scp->phys_addr, GFP_KERNEL);
      |         ^~~~~~~~~~~~~~~
      |         |
      |         phys_addr_t * {aka unsigned int *}
In file included from drivers/remoteproc/mtk_scp.c:7:
include/linux/dma-mapping.h:642:15: note: expected 'dma_addr_t *' {aka 'long long unsigned int *'} but argument is of type 'phys_addr_t *' {aka 'unsigned int *'}
  642 |   dma_addr_t *dma_handle, gfp_t gfp)

Change the phys_addr member to be typed and named according
to how it is allocated.

Fixes: d5357ff61742 ("remoteproc/mediatek: add SCP support for mt8183")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200408155450.2186471-1-arnd@arndb.de
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>