drm/i915: Attempt to fix watermark setup on 85x (v2)

IS_MOBILE() catches 85x, so we'd always try to use the 9xx FIFO sizing;
since there's an explicit 85x version, this seems wrong.

v2: Handle 830m correctly too.
Signed-off-by: NAdam Jackson <ajax@redhat.com>
Reviewed-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NEric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/intel_display.c

@@ -4853,17 +4853,18 @@ static void intel_init_display(struct drm_device *dev)
 		dev_priv->display.update_wm = g4x_update_wm;
 	else if (IS_I965G(dev))
 		dev_priv->display.update_wm = i965_update_wm;
-	else if (IS_I9XX(dev) || IS_MOBILE(dev)) {
+	else if (IS_I9XX(dev)) {
 		dev_priv->display.update_wm = i9xx_update_wm;
 		dev_priv->display.get_fifo_size = i9xx_get_fifo_size;
+	} else if (IS_I85X(dev)) {
+		dev_priv->display.update_wm = i9xx_update_wm;
+		dev_priv->display.get_fifo_size = i85x_get_fifo_size;
 	} else {
-		if (IS_I85X(dev))
-			dev_priv->display.get_fifo_size = i85x_get_fifo_size;
-		else if (IS_845G(dev))
+		dev_priv->display.update_wm = i830_update_wm;
+		if (IS_845G(dev))
 			dev_priv->display.get_fifo_size = i845_get_fifo_size;
 		else
 			dev_priv->display.get_fifo_size = i830_get_fifo_size;
-		dev_priv->display.update_wm = i830_update_wm;
 	}
 }