drm/amdgpu: implement the allocation range (v3)

Pass a ttm_placement pointer to amdgpu_bo_create_restricted
add min_offset to amdgpu_bo_pin_restricted.  This makes it
easier to allocate memory with address restrictions.  With
this patch we can also enable 2-ended allocation again.

v2: fix rebase conflicts
v3: memset placements before using

Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
Signed-off-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>