drm/i915/icl: Don't wait for empty FIFO

For Gen11 DSI, we don't need to wait for getting
DSI FIFO empty after sending DCS commands.
Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/5e078a0274c1fba2521cb14d7d02fd1038ec1b0e.1540900289.git.jani.nikula@intel.com

drivers/gpu/drm/i915/intel_dsi_vbt.c

@@ -111,6 +111,7 @@ static inline enum port intel_dsi_seq_port_to_port(u8 port)
 static const u8 *mipi_exec_send_packet(struct intel_dsi *intel_dsi,
 				       const u8 *data)
 {
+	struct drm_i915_private *dev_priv = to_i915(intel_dsi->base.base.dev);
 	struct mipi_dsi_device *dsi_device;
 	u8 type, flags, seq_port;
 	u16 len;
@@ -181,7 +182,8 @@ static const u8 *mipi_exec_send_packet(struct intel_dsi *intel_dsi,
 		break;
 	}
 
-	vlv_dsi_wait_for_fifo_empty(intel_dsi, port);
+	if (!IS_ICELAKE(dev_priv))
+		vlv_dsi_wait_for_fifo_empty(intel_dsi, port);
 
 out:
 	data += len;