drm/radeon/kms: add missing external encoder action

required for ddc.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atombios.h

@@ -1200,6 +1200,7 @@ typedef struct _EXTERNAL_ENCODER_CONTROL_PARAMETERS_V3
 #define EXTERNAL_ENCODER_ACTION_V3_ENCODER_BLANKING_OFF   0x10
 #define EXTERNAL_ENCODER_ACTION_V3_ENCODER_BLANKING       0x11
 #define EXTERNAL_ENCODER_ACTION_V3_DACLOAD_DETECTION      0x12
+#define EXTERNAL_ENCODER_ACTION_V3_DDC_SETUP              0x14
 
 // ucConfig
 #define EXTERNAL_ENCODER_CONFIG_V3_DPLINKRATE_MASK				0x03