Add a new address space for NPA address management. This is needed for sharing buffer objects across GPUs with each running their own OS. The NPA address space size can change across different HW generations so the size is initialized during early init of the driver boot up process. Signed-off-by: Mukul Joshi <mukul.joshi@amd.com> Reviewed-by: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>