bcma: make bcma_host_pci_(up|down) calls safe for every config

We were providing declarations but actual code was compiled only with
CONFIG_BCMA_HOST_PCI set. This could result in:
ERROR: "bcma_host_pci_down" [drivers/net/wireless/brcm80211/brcmsmac/brcmsmac.ko] undefined!
ERROR: "bcma_host_pci_up" [drivers/net/wireless/brcm80211/brcmsmac/brcmsmac.ko] undefined!
ERROR: "bcma_host_pci_down" [drivers/net/wireless/b43/b43.ko] undefined!
ERROR: "bcma_host_pci_up" [drivers/net/wireless/b43/b43.ko] undefined!

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

include/linux/bcma/bcma.h

@@ -434,8 +434,17 @@ static inline struct bcma_device *bcma_find_core(struct bcma_bus *bus,
 	return bcma_find_core_unit(bus, coreid, 0);
 }
 
+#ifdef CONFIG_BCMA_HOST_PCI
 extern void bcma_host_pci_up(struct bcma_bus *bus);
 extern void bcma_host_pci_down(struct bcma_bus *bus);
+#else
+static inline void bcma_host_pci_up(struct bcma_bus *bus)
+{
+}
+static inline void bcma_host_pci_down(struct bcma_bus *bus)
+{
+}
+#endif
 
 extern bool bcma_core_is_enabled(struct bcma_device *core);
 extern void bcma_core_disable(struct bcma_device *core, u32 flags);