baytrail: Add ACPI Device for XHCI

This will allow USB devices to wake the system (if 5V is not turned off)
and the controller to enter D3 at runtime. (if autosuspend is enabled)

BUG=chrome-os-partner:23629
BRANCH=baytrail
TEST=build and boot on baytrail

1) with modified EC to leave 5V on in S3 ensure that waking from suspend
with USB keyboard works.
2) with laptop-mode-tools usb autosuepend config updated see that device
enters D3 at runtime when no external devices attached.

Change-Id: Ia396d42494e30105f06eb3bd65b4ba8b1372cf35
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/182536
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/5046
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
diff --git a/src/soc/intel/baytrail/acpi/southcluster.asl b/src/soc/intel/baytrail/acpi/southcluster.asl
index ced1618..61642a5 100644
--- a/src/soc/intel/baytrail/acpi/southcluster.asl
+++ b/src/soc/intel/baytrail/acpi/southcluster.asl
@@ -252,6 +252,9 @@
 // LPC Bridge 0:1f.0
 #include "lpc.asl"
 
+// USB XHCI 0:14.0
+#include "xhci.asl"
+
 // IRQ routing for each PCI device
 #include "irqroute.asl"