staging: usbip: userspace: utils: remove libsysfs circumvention

Removes all of the helper functions that used a lot of hard-coded
values intead of libsysfs. Most of these functions were unused
anyway.

Signed-off-by: matt mooney <mfm@muteddisk.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>