drm/amd/amdgpu: Remove AMDGPU tracepoint and use new TTM tracepoint (v2)

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.