AMD Hudson: Add config option to enable XHCI

To have USB 3.0 support the XHCI controller needs to be enabled
and the xhci.bin firmware needs to be added to CBFS.

Change-Id: I0b641b30b67163b7dc73ee7ae67efe678e11c000
Signed-off-by: Dave Frodin <dave.frodin@se-eng.com>
Reviewed-on: http://review.coreboot.org/3464
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/src/southbridge/amd/agesa/hudson/Kconfig b/src/southbridge/amd/agesa/hudson/Kconfig
index 7aa3405..b346863 100644
--- a/src/southbridge/amd/agesa/hudson/Kconfig
+++ b/src/southbridge/amd/agesa/hudson/Kconfig
@@ -40,11 +40,21 @@
 	hex
 	default 0xe0
 
+config HUDSON_XHCI_ENABLE
+	bool "Enable Hudson XHCI Controller"
+	default y
+	help
+	  The XHCI controller must be enabled and the XHCI firmware
+	  must be added in order to have USB 3.0 support configured
+	  by coreboot. The OS will be responsible for enabling the XHCI
+	  controller if the the XHCI firmware is available but the
+	  XHCI controller is not enabled by coreboot.
+
 config HUDSON_XHCI_FWM
 	bool "Add xhci firmware"
 	default y
-        help
-	  Add Hudson 2/3/4 XHCI Firmware to support the onboard usb3.0
+	help
+	  Add Hudson 2/3/4 XHCI Firmware to support the onboard USB 3.0
 
 config HUDSON_IMC_FWM
 	bool "Add imc firmware"