drm/i915: Use IS_GEN9_LP() for the linetime w/a check

IS_GLK||IS_BXT == IS_GEN9_LP
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181221171436.8218-10-ville.syrjala@linux.intel.comReviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>

drivers/gpu/drm/i915/intel_pm.c

@@ -4826,9 +4826,8 @@ skl_compute_linetime_wm(const struct intel_crtc_state *cstate)
 	linetime_us = intel_get_linetime_us(cstate);
 	linetime_wm = fixed16_to_u32_round_up(mul_u32_fixed16(8, linetime_us));
 
-	/* Display WA #1135: bxt:ALL GLK:ALL */
-	if ((IS_BROXTON(dev_priv) || IS_GEMINILAKE(dev_priv)) &&
-	    dev_priv->ipc_enabled)
+	/* Display WA #1135: BXT:ALL GLK:ALL */
+	if (IS_GEN9_LP(dev_priv) && dev_priv->ipc_enabled)
 		linetime_wm /= 2;
 
 	return linetime_wm;