drm/amd/display: Fix NULL deref of new_stream->sink in VTEM guard

[Why & How]
amdgpu_dm_update_freesync_state_on_stream() keyed the VTEM guard off
new_stream->sink->sink_signal, but new_stream->sink can be NULL, leading
to a NULL pointer dereference.

Use new_stream->signal instead, which is a direct field of the already
validated new_stream and carries the same HDMI signal type. This matches
the ALLM block in the same function, which already uses new_stream->signal.

Fixes: 640fd039dc8b ("drm/amd/display: Emit VTEM for HF-VSDB VRR on TMDS links")
Reviewed-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Signed-off-by: Ray Wu <ray.wu@amd.com>
Tested-by: Dan Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

0 files changed, 0 insertions, 0 deletions