drm/i915/sdvo: Don't unpack stack garbage

Pass the length returned by intel_sdvo_read_infoframe() to
hdmi_infoframe_unpack() so that we don't try to unpack any
leftover stack garbage.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190409144054.24561-6-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1132,7 +1132,7 @@ static void intel_sdvo_get_avi_infoframe(struct intel_sdvo *intel_sdvo,
 	crtc_state->infoframes.enable |=
 		intel_hdmi_infoframe_enable(HDMI_INFOFRAME_TYPE_AVI);
 
-	ret = hdmi_infoframe_unpack(frame, sdvo_data, sizeof(sdvo_data));
+	ret = hdmi_infoframe_unpack(frame, sdvo_data, len);
 	if (ret) {
 		DRM_DEBUG_KMS("Failed to unpack AVI infoframe\n");
 		return;