ALSA: Add #ifdef CONFIG_PCI guard for snd_pci_quirk_* functions

This fixes below build warning when CONFIG_PCI is not set.

CC      sound/sound_core.o
In file included from sound/sound_core.c:15:
include/sound/core.h:454: warning: 'struct pci_dev' declared inside parameter list
include/sound/core.h:454: warning: its scope is only this definition or declaration, which is probably not what you want

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/core.h

@@ -417,6 +417,7 @@ static inline int __snd_bug_on(int cond)
 #define gameport_get_port_data(gp) (gp)->port_data
 #endif
 
+#ifdef CONFIG_PCI
 /* PCI quirk list helper */
 struct snd_pci_quirk {
 	unsigned short subvendor;	/* PCI subvendor ID */
@@ -456,5 +457,6 @@ snd_pci_quirk_lookup(struct pci_dev *pci, const struct snd_pci_quirk *list);
 const struct snd_pci_quirk *
 snd_pci_quirk_lookup_id(u16 vendor, u16 device,
 			const struct snd_pci_quirk *list);
+#endif
 
 #endif /* __SOUND_CORE_H */