baytrail: Add XHCI initialization

This adds required steps to initialize the XHCI controller
on the baytrail platform.

Actually using XHCI is causing lots of bad behavior including
apparent memory corruption.

BUG=chrome-os-partner:23635
BRANCH=rambi
TEST=build and boot on rambi

Change-Id: Ic43e04f4b47e107ec3bb0c387a9fc72c3cae0271
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/175511
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/4929
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/soc/intel/baytrail/chip.h

@@ -29,6 +29,13 @@ struct soc_intel_baytrail_config {
         uint8_t sata_port_map;
         uint8_t sata_ahci;
         uint8_t ide_legacy_combined;
+
+	/* USB Port Disable mask */
+	uint16_t usb2_port_disable_mask;
+	uint16_t usb3_port_disable_mask;
+
+	/* USB routing */
+	int usb_route_to_xhci;
 };
 
 extern struct chip_operations soc_intel_baytrail_ops;