drivers/mtd_flashpage: add mtd_flashpage_t type
drivers/mtd_flashpage: add mtd_flashpage_t type

jasonatran/RIOT,ant9000/RIOT,kaspar030/RIOT,kaspar030/RIOT,miri64/RIOT,OlegHahm/RIOT,kYc0o/RIOT,miri64/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,ant9000/RIOT,kYc0o/RIOT,miri64/RIOT,kYc0o/RIOT,jasonatran/RIOT,kYc0o/RIOT,ant9000/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,miri64/RIOT,miri64/RIOT,jasonatran/RIOT,ant9000/RIOT,OlegHahm/RIOT,jasonatran/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,kaspar030/RIOT,ant9000/RIOT