drm/amdgpu: restrict bo mapping within gpu address limits

drm/amdgpu: restrict bo mapping within gpu address limits

Have strict check on bo mapping since on some systems, such as A+A or
hybrid, the cpu might support 5 level paging or can address memory above
48 bits but gpu might be limited by hardware to just use 48 bits. In
general, this applies to all asics where this limitation can be checked
against their max_pfn range. This restricts the range to map bo within
pratical limits of cpu and gpu for shared virtual memory access.

Reviewed-by: Oak Zeng <oak.zeng@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>