firmware: provide stubs for the FW_LOADER=n case

libsas has a case where it uses the firmware loader to provide services,
but doesn't want to select it all the time.  This currently causes a
compile failure in libsas if FW_LOADER=n.  Fix this by providing error
stubs for the firmware loader API in the FW_LOADER=n case.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

include/linux/firmware.h

@@ -10,7 +10,10 @@ struct firmware {
 	size_t size;
 	u8 *data;
 };
+
 struct device;
+
+#if defined(CONFIG_FW_LOADER) || defined(CONFIG_FW_LOADER_MODULE)
 int request_firmware(const struct firmware **fw, const char *name,
 		     struct device *device);
 int request_firmware_nowait(
@@ -19,4 +22,24 @@ int request_firmware_nowait(
 	void (*cont)(const struct firmware *fw, void *context));
 
 void release_firmware(const struct firmware *fw);
+#else
+static inline int request_firmware(const struct firmware **fw,
+				   const char *name,
+				   struct device *device)
+{
+	return -EINVAL;
+}
+static inline int request_firmware_nowait(
+	struct module *module, int uevent,
+	const char *name, struct device *device, void *context,
+	void (*cont)(const struct firmware *fw, void *context))
+{
+	return -EINVAL;
+}
+
+static inline void release_firmware(const struct firmware *fw)
+{
+}
+#endif
+
 #endif