[ALSA] hda-intel - Fix pci_disable_msi() call

Fix the order to call pci_disable_msi() to be after free_irq().
(Otherwise pci_disable_msi() bugs you.)
Also, added a description of disable_msi option to documentation.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index cc50d13..bfd74a5 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -1422,8 +1422,9 @@
 	}
 
 	if (chip->irq >= 0) {
-		pci_disable_msi(chip->pci);
 		free_irq(chip->irq, (void*)chip);
+		if (!disable_msi)
+			pci_disable_msi(chip->pci);
 	}
 	if (chip->remap_addr)
 		iounmap(chip->remap_addr);