usb: cdns3: include host-export,h for cdns3_host_init

The cdns3_host_init() function is declared in host-export.h
but host.c does not include it. Add the include to have
the declaration present (and remove the declaration of
cdns3_host_exit which is now static).

Fixes the following sparse warning:

drivers/usb/cdns3/host.c:58:5: warning: symbol 'cdns3_host_init' was not declared. Should it be static?
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/cdns3/host-export.h

@@ -12,7 +12,6 @@
 #ifdef CONFIG_USB_CDNS3_HOST
 
 int cdns3_host_init(struct cdns3 *cdns);
-void cdns3_host_exit(struct cdns3 *cdns);
 
 #else
 

drivers/usb/cdns3/host.c

@@ -12,6 +12,7 @@
 #include <linux/platform_device.h>
 #include "core.h"
 #include "drd.h"
+#include "host-export.h"
 
 static int __cdns3_host_init(struct cdns3 *cdns)
 {