[Cin] patch for 44.1/32 khz pcm input in pcm dvd encoder

relative to ffmpeg.git commit 6c4388b468bf92c0c1e7733c6cfe4ff3f9ca9723 lightly tested with mpv and mediainfo like this: ./ffmpeg -i ~/f9518976.mp4 -target pal-dvd -ar 44100 -c:a pcm_dvd -f dvd t.mpg mpv plays sound correctly, mediainfo does not know those frequencies and display 0khz. ;)