[usb] Add config/usb.h for USB configuration options

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/config/config_usb.c

@@ -21,7 +21,7 @@
 
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
-#include <config/general.h>
+#include <config/usb.h>
 
 /** @file
  *

src/config/usb.h

@@ -0,0 +1,25 @@
+#ifndef CONFIG_USB_H
+#define CONFIG_USB_H
+
+/** @file
+ *
+ * USB configuration
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <config/defaults.h>
+
+/*
+ * USB host controllers (all enabled by default)
+ *
+ */
+//#undef	USB_HCD_XHCI		/* xHCI USB host controller */
+
+#include <config/named.h>
+#include NAMED_CONFIG(usb.h)
+#include <config/local/usb.h>
+#include LOCAL_NAMED_CONFIG(usb.h)
+
+#endif /* CONFIG_USB_H */