m7 / dlx: fix USB OTG host mode

The Kconfig option was removed in commit:

    commit c701879c0073dc0bb03c895e6c7bd101d32d437d
    Author: Daniel Hillenbrand <codeworkx@cyanogenmod.org>
    Date:   Sun May 5 11:39:29 2013 +0200

        defuxx usb, break all teh things

Change-Id: I38676e5384675abcfb04bd99b7537e60eef6c643