firmware loader: fix compile warning with PM_SLEEP set

This patch fixes the below compile warning:

drivers/base/firmware_class.c:1254:12: warning: 'cache_firmware' defined
but not used [-Wunused-function]
 static int cache_firmware(const char *fw_name)
            ^
drivers/base/firmware_class.c:1281:12: warning: 'uncache_firmware'
defined but not used [-Wunused-function]
 static int uncache_firmware(const char *fw_name)
            ^

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/base/firmware_class.c

@@ -1247,6 +1247,9 @@ request_firmware_nowait(
 }
 EXPORT_SYMBOL(request_firmware_nowait);
 
+#ifdef CONFIG_PM_SLEEP
+static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
+
 /**
  * cache_firmware - cache one firmware image in kernel memory space
  * @fw_name: the firmware image name
@@ -1307,9 +1310,6 @@ static int uncache_firmware(const char *fw_name)
 	return -EINVAL;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static ASYNC_DOMAIN_EXCLUSIVE(fw_cache_domain);
-
 static struct fw_cache_entry *alloc_fw_cache_entry(const char *name)
 {
 	struct fw_cache_entry *fce;