tensorflow: update XNNPACK and install headers / libs

This CL updates the XNNPACK dependency of Tensorflow to commit
79cd5f9e18ad0925ac9a050b00ea5a36230072db, which includes fixes to
its quantized implementation.

This CL also installs the XNNPACK headers and libs when built with the
'xnnpack' USE flag.

TEST=cq passes

Change-Id: I30fa8c30950f59d8b1e5d006b3f94e2895a2b7db
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/chromiumos-overlay/+/2790824
Tested-by: Jim Pollock <jmpollock@chromium.org>
Auto-Submit: Jim Pollock <jmpollock@chromium.org>
Reviewed-by: Stuart Langley <slangley@chromium.org>
4 files changed