ASoC: dapm: Remove always true path source/sink checks

A path has always a valid source and a valid sink otherwise we wouldn't add it
in the first place. Hence all tests that check if sink/source is NULL always
evaluate to true and can be removed.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
ASoC: dapm: Power up vmid/siggen widgets only when on an active path

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
ASoC: parent check
ASoC: Add CTDM bus support

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
ASoC: Add ssm4567 driver

This patch adds support for the ssm4567. The ssm4567 is a class D audio
amplifier with an I2S interface for audio in.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
ASoC: Add ssm4329 driver

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>