drm/amdgpu: amdgpu_vram_mgr_new(): Clamp lpfn to total vram

drm/amdgpu: amdgpu_vram_mgr_new(): Clamp lpfn to total vram

commit 4d2f6b4e4c7ed32e7fa39fcea37344a9eab99094 upstream.

The drm_mm allocator tolerated being passed end > mm->size, but the
drm_buddy allocator does not.

Restore the pre-buddy-allocator behavior of allowing such placements.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3448
Signed-off-by: John Olender <john.olender@gmail.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>