Revert "libstagefright: set frame packing from codec config"

 * With Venus 1.6, this patch causes the decoder to freeze
   during a new CTS case. Since we aren't using frame packing
   anyway, revert this.

This reverts commit 8356ac84.

Change-Id: I661c84727976aab8a81824279ee1a2fefdd5f8a3