drm/i915: remove unused DDC PIN macros

Their user has vanished in the course of history. Remove.
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181115105237.1237-2-jani.nikula@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -1060,10 +1060,6 @@ struct i915_gem_mm {
 #define DP_AUX_E 0x50
 #define DP_AUX_F 0x60
 
-#define DDC_PIN_B  0x05
-#define DDC_PIN_C  0x04
-#define DDC_PIN_D  0x06
-
 struct ddi_vbt_port_info {
 	int max_tmds_clock;