USB: make hcd.h public (drivers dependency)

The usbcore headers: hcd.h and hub.h are shared between usbcore,
HCDs and a couple of other drivers (e.g. USBIP modules).
So, it makes sense to move them into a more public location and
to cleanup dependency of those modules on kernel internal headers.
This patch moves hcd.h from drivers/usb/core into include/linux/usb/

Signed-of-by: Eric Lescouet <eric@lescouet.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c
index 0d3af6a..77e0dda 100644
--- a/drivers/usb/core/config.c
+++ b/drivers/usb/core/config.c
@@ -1,12 +1,13 @@
 #include <linux/usb.h>
 #include <linux/usb/ch9.h>
+#include <linux/usb/hcd.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/device.h>
 #include <asm/byteorder.h>
 #include "usb.h"
-#include "hcd.h"
+
 
 #define USB_MAXALTSETTING		128	/* Hard limit */
 #define USB_MAXENDPOINTS		30	/* Hard limit */