drm/amdkfd: Fix printing pointer cast

Just print a pointer instead of casting

v2: Remove the 0x prefix, since %p prints that automatically, and remove
it from one other spot as well

Signed-off-by: Kent Russell <kent.russell@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>