USB: OHCI: omap: remove useless extern declaration

Remove usb_disabled() and ocpi_enable() extern declaration
as it is already declared as EXPORT_SYMBOL_GPL declaration.

Signed-off-by: Manjunath Goudar <csmanjuvijay@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: linux-usb@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>