libva: update to 1.8.2.

Version 1.8.2 - 22.May.2017
* Bump libva to 1.8.2

Version 1.8.1 - 10.Apr.2017
* Bump libva to 1.8.1

Version 1.8.0 - 31.March.2017
* Bump VA API version to 0.40
* API: Change vaRenderPicture semantics that vaRenderPicture no longer deletes the passed buffer automatically.
* API: Add VA_FOURCC_I010 for 10bit surface
* API: Add vaSetErrorCallback and vaSetInfoCallback for error and info message.
* va/drm: Update the support for Mesa Gallium driver
* va/drm: Fix authentication check for /dev/dri/card0
* Move all utilities and tests to libva-utils (https://github.com/01org/libva-utils)

(wiz)