va: filter: don't destroy pipeline buffer
This was only required by i915 driver before libva-2.0 because it didn't conform.
Also changes the way _destroy_filters() is called, now inside a locked block, so it must not lock in it.
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This was only required by i915 driver before libva-2.0 because it didn't conform.
Also changes the way _destroy_filters() is called, now inside a locked block, so it must not lock in it.