drm/amd/display: Log DTN only after the atomic commit in Diag

Also print HUBP info only if pipe enabled. This fixes having different
DTN logs for different test sequences.

Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>