ARM: s3c64xx: Drop initialization of unused struct s3c_audio_pdata fields

Remove initialization of dma_{filter, playback, capture, capture_mic}
fields where it is not used any more.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>