Update PIEX

* Adjust the max thumbnail size to 512 pixel
* Reads the correct full dimensions for DNGs which are stored in DefaultCropSize of the main image

Cherry-pick of be908191d0a6883a95333bdc0bca749c9b830969 from public AOSP

This change should fix the issue of Skia getPixels() / getAndroidPixels()
It is already tested and used by the up-stream Skia since http://crrev.com/1883783002

Bug: 28162811, Bug: 28119810
Change-Id: I78caa62eb79ae0b6c8cf718a2ba82c0b6bde9f27