Revert "tests/iio_info: Add support for the USB backend"
Revert "tests/iio_info: Add support for the USB backend"

This reverts commit e6e94eb5e9840d6a21085fdb1d18c2f05cccb62d.

The current USB context API is being dropped in favour of a better more
flexible interface.

Signed-off-by: Lars-Peter Clausen <3318dc5ce3e4fb7c28a0b841b6801c884e1d0896@metafoo.de>

analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio