Reported by Nikolaus Schaller, Sep 10, 2014

it appears as if the itg3200 is always powered on and not in sleep 
mode.

There is a patch proposed for 3.12:

http://lists.goldelico.com/pipermail/gta04-owner/2014-September/00586
4.html

but the solution must be adapted for the 3.17 driver. AFAIK, turing 
the ITG into sleep mode must be added to 

itg3200_write_raw / case IIO_CHAN_INFO_SAMP_FREQ:

What we also should look is if the kernel suspend mechanism does the 
same (maybe through the IIO framework?).