[ALSA] Xilinx ML403 AC97 Controller Reference device driver

Add ALSA support for the opb_ac97_controller_ref_v1_00_a ip core found
in Xilinx' ML403 reference design.
Known issue: Currently this driver hits a WARN_ON_ONCE(1) statement in
kernel/irq/resend.c (line 70). According to Linus
(http://lkml.org/lkml/2007/8/5/5) this may be ignored, right? I haven't
had a look into this 'problem' yet.

Signed-off-by: Joachim Foerster <JOFT@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/drivers/Kconfig b/sound/drivers/Kconfig
index 83529b0..75d4fe0 100644
--- a/sound/drivers/Kconfig
+++ b/sound/drivers/Kconfig
@@ -120,4 +120,16 @@
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-portman2x4.
 
+config SND_ML403_AC97CR
+	tristate "Xilinx ML403 AC97 Controller Reference"
+	depends on SND && XILINX_VIRTEX
+	select SND_AC97_CODEC
+	help
+	  Say Y here to include support for the
+	  opb_ac97_controller_ref_v1_00_a ip core found in Xilinx' ML403
+	  reference design.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-ml403_ac97cr.
+
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