drm/msm: Fix a couple of 64-bit build warnings

Avoid casts from pointers to fixed-size integers to prevent the compiler
from warning. Print virtual memory addresses using %p instead. Also turn
a couple of %d/%x specifiers into %zu/%zd/%zx to avoid further warnings
due to mismatched format strings.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>