ALSA: fireworks: Add PCM interface

This commit adds a functionality to capture/playback PCM samples.

When AMDTP stream is already running for PCM or the source of clock is not
internal, available sampling rate is limited at current one.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/firewire/Kconfig b/sound/firewire/Kconfig
index 36a1212..fb39f9c 100644
--- a/sound/firewire/Kconfig
+++ b/sound/firewire/Kconfig
@@ -65,6 +65,7 @@
 	tristate "Echo Fireworks board module support"
 	select SND_FIREWIRE_LIB
 	select SND_RAWMIDI
+	select SND_PCM
 	help
 	  Say Y here to include support for FireWire devices based
 	  on Echo Digital Audio Fireworks board: