drm/amd/display: Adding HDMI SCDC DEVICE_ID define

[Why && How]
We will need to differentiate vendor behavior in the future.
Reviewed-by: Chris Park <Chris.Park@amd.com>
Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Leo Ma <hanghong.ma@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_link_ddc.c

@@ -82,6 +82,7 @@ struct dp_hdmi_dongle_signature_data {
 #define HDMI_SCDC_STATUS_FLAGS 0x40
 #define HDMI_SCDC_ERR_DETECT 0x50
 #define HDMI_SCDC_TEST_CONFIG 0xC0
+#define HDMI_SCDC_DEVICE_ID 0xD3
 
 union hdmi_scdc_update_read_data {
 	uint8_t byte[2];