x86: rv40dsp: Use PAVGB instruction macro where appropriate
vdpau: Add missing #includes to fix standalone header compilation

Signed-off-by: Anton Khirnov <anton@khirnov.net>
graph2dot: Fix use of deprecated API
graph2dot: Add missing #include for av_get_channel_layout_string()
avfilter/buffer: Suppress deprecation warning for avfilter_unref_buffer

The function is used in a block of code that is deprecated anyway.