ALSA: hda - Modularize HD-audio driver

Split the monolithc HD-audio driver into several pieces:
 - snd-hda-intel   HD-audio PCI controller driver; loaded via udev
 - snd-hda-codec   HD-audio codec bus driver
 - snd-hda-codec-* Specific HD-audio codec drivers

When built as modules, snd-hda-codec (that is invoked by snd-hda-intel)
looks up the codec vendor ID and loads the corresponding codec module
automatically via request_module().

When built in a kernel, each codec drivers are statically hooked up
before probing the PCI.

This patch adds appropriate EXPORT_SYMBOL_GPL()'s and the module
information for each driver, and driver-linking codes between
codec-bus and codec drivers.

TODO:
  - Avoid EXPORT_SYMBOL*() when built-in kernel
  - Restore __devinit appropriately depending on the condition

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
index 9fe0b67..586ea08 100644
--- a/sound/pci/hda/hda_codec.h
+++ b/sound/pci/hda/hda_codec.h
@@ -642,6 +642,16 @@
 	int (*patch)(struct hda_codec *codec);
 };
 	
+struct hda_codec_preset_list {
+	const struct hda_codec_preset *preset;
+	struct module *owner;
+	struct list_head list;
+};
+
+/* initial hook */
+int snd_hda_add_codec_preset(struct hda_codec_preset_list *preset);
+int snd_hda_delete_codec_preset(struct hda_codec_preset_list *preset);
+
 /* ops set by the preset patch */
 struct hda_codec_ops {
 	int (*build_controls)(struct hda_codec *codec);
@@ -735,6 +745,7 @@
 
 	/* detected preset */
 	const struct hda_codec_preset *preset;
+	struct module *owner;
 	const char *name;	/* codec name */
 	const char *modelname;	/* model name for preset */