[media] solo6x10: Convert to the new PCM ops

Replace the copy and the silence ops with the new PCM ops.
The device supports only 1 channel and 8bit sample, so it's always
bytes=frames, and we need no conversion of unit in the callback.
Also, it's a capture stream, thus no silence is needed.

Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>