drm/i915: Rename defines for selection of ddi buffer translation slot

Renaming the HSW-specific macros for ddi buffer translation slot to denote the
slot and not the vswing/pre-emph values as they are platform-dependent.

This patch is based on top of the patch series for renaming the DP training
vswing/pre-emph defines:
http://lists.freedesktop.org/archives/intel-gfx/2014-August/050407.html

v2: Creating single macro with argument for slot number (Damien)
v3: Adding macro for num of translation entries (Damien)

Signed-off-by: Sonika Jindal <sonika.jindal@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -2892,29 +2892,29 @@ intel_hsw_signal_levels(uint8_t train_set)
 					 DP_TRAIN_PRE_EMPHASIS_MASK);
 	switch (signal_levels) {
 	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
-		return DDI_BUF_EMP_400MV_0DB_HSW;
+		return DDI_BUF_TRANS_SELECT(0);
 	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
-		return DDI_BUF_EMP_400MV_3_5DB_HSW;
+		return DDI_BUF_TRANS_SELECT(1);
 	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
-		return DDI_BUF_EMP_400MV_6DB_HSW;
+		return DDI_BUF_TRANS_SELECT(2);
 	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_9_5:
-		return DDI_BUF_EMP_400MV_9_5DB_HSW;
+		return DDI_BUF_TRANS_SELECT(3);
 
 	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
-		return DDI_BUF_EMP_600MV_0DB_HSW;
+		return DDI_BUF_TRANS_SELECT(4);
 	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
-		return DDI_BUF_EMP_600MV_3_5DB_HSW;
+		return DDI_BUF_TRANS_SELECT(5);
 	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_6:
-		return DDI_BUF_EMP_600MV_6DB_HSW;
+		return DDI_BUF_TRANS_SELECT(6);
 
 	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
-		return DDI_BUF_EMP_800MV_0DB_HSW;
+		return DDI_BUF_TRANS_SELECT(7);
 	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
-		return DDI_BUF_EMP_800MV_3_5DB_HSW;
+		return DDI_BUF_TRANS_SELECT(8);
 	default:
 		DRM_DEBUG_KMS("Unsupported voltage swing/pre-emphasis level:"
 			      "0x%x\n", signal_levels);
-		return DDI_BUF_EMP_400MV_0DB_HSW;
+		return DDI_BUF_TRANS_SELECT(0);
 	}
 }