Revert "Rockchip: Force first 3x3 array of macroblocks of frame to be intra blocks"

This reverts commit 819d3d20.

We have implemented proper workaround in kernel driver, so the old
one in the plugin is not needed anymore.

BUG=chrome-os-partner:41585
TEST=Play video on vimeo and cast on extreme setting

Change-Id: I76179a0afe285aff217518345d3567d806a4f641
Reviewed-on: https://chromium-review.googlesource.com/289438


Tested-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Pawel Osciak <posciak@chromium.org>
Trybot-Ready: Pawel Osciak <posciak@chromium.org>
Commit-Queue: Tomasz Figa <tfiga@chromium.org>