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>

drivers/usb/host/uhci-hcd.c

@@ -38,6 +38,7 @@
 #include <linux/dmapool.h>
 #include <linux/dma-mapping.h>
 #include <linux/usb.h>
+#include <linux/usb/hcd.h>
 #include <linux/bitops.h>
 #include <linux/dmi.h>
 
@@ -46,7 +47,6 @@
 #include <asm/irq.h>
 #include <asm/system.h>
 
-#include "../core/hcd.h"
 #include "uhci-hcd.h"
 #include "pci-quirks.h"