drm/amd/display: Add tracepoint for amdgpu_dm

Debug amdgpu_dm could be a complicated task, therefore, this commit adds
tracepoints in some convenient functions such as plane and connector
check inside amdgpu_dm.

Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>