ALSA: hda_intel: add card number to irq description

Currently the info in /proc/interrupts doesn't allow to figure out which
interrupt belongs to which card (HDMI, PCH, ..).
Therefore add card details to the interrupt description.
With the patch the info in /proc/interrupts looks like this:

PCI-MSI 442368-edge      snd_hda_intel:card1
PCI-MSI 49152-edge      snd_hda_intel:card0

NOTE: this patch adds the new irq_descr field snd_card struct that is
filled automatically at a card object creation.  This can be used
generically for other drivers as well.  The changes for others will
follow later -- tiwai

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/init.c b/sound/core/init.c
index 20f37fb..6bda843 100644
--- a/sound/core/init.c
+++ b/sound/core/init.c
@@ -268,6 +268,9 @@
 	if (err < 0)
 		goto __error;
 
+	snprintf(card->irq_descr, sizeof(card->irq_descr), "%s:%s",
+		 dev_driver_string(card->dev), dev_name(&card->card_dev));
+
 	/* the control interface cannot be accessed from the user space until */
 	/* snd_cards_bitmask and snd_cards are set with snd_card_register */
 	err = snd_ctl_create(card);