usb: mv-otg - Fix build if CONFIG_USB is not set

ERROR: "usb_remove_hcd" [drivers/usb/otg/mv_otg.ko] undefined!
ERROR: "usb_add_hcd" [drivers/usb/otg/mv_otg.ko] undefined!

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
--
Inpired by drivers/usb/otg/msm_otg.c. Is this correct?

 drivers/usb/otg/mv_otg.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>