usb: usbip: fix usbip.h path in userspace tool

Fixes: 588b48caf65c ("usbip: move usbip userspace code out of staging")
which introduced build failure by not changing uapi/usbip.h include path
according to new location.

Signed-off-by: Piotr Król <piotr.krol@3mdeb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 24e9033..9955c3b 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -395,6 +395,7 @@
 header-y += unistd.h
 header-y += unix_diag.h
 header-y += usbdevice_fs.h
+header-y += usbip.h
 header-y += utime.h
 header-y += utsname.h
 header-y += uuid.h