drm/msm: Replace type of paddr to uint32_t.

This patch helps to avoid the following build issue:

drivers/gpu/drm/msm/msm_fbdev.c:108:2: error: passing argument 3 of 'msm_gem_get_iova_locked' from incompatible pointer type [-Werror]
   msm_gem_get_iova_locked(fbdev->bo, 0, &paddr);
   ^
In file included from drivers/gpu/drm/msm/msm_fbdev.c:18:0:
drivers/gpu/drm/msm/msm_drv.h:153:5: note: expected 'uint32_t *' but argument is of type 'dma_addr_t *'
  int msm_gem_get_iova_locked(struct drm_gem_object *obj, int id,
      ^

Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
Signed-off-by: Rob Clark <robdclark@gmail.com>