inkern: iio_device_put after incorrect return/goto

The code uses

    return foo;
    goto err_type;

when instead the form should have been

    ret = foo;
    goto err_type;

Here this causes a useful iio_device_put to be skipped.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>