Switches the AMDGPU driver over to the TTM tracepoint and removes
our old one.  Now you can enable traces before loading the module
and trace all mappings.
Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

(v2): Use struct device instead of pci in trace.