Remove a gfree call done from an object now "owning" the mem

A new char is created, gstrdupprintf, and is freed in multiple locations including from inside iiobufferutils.

As a solution we strdup a string from the sysfs attribute "name" and then never free it. It's assumed that every device is discovered only once, a check for this device being previously discovered could be added. The change from using the created char to the char from sysfs is to provide a means to have multiple created strings, a later patch for mpu6050 support.