[PATCH] isdn4linux: Gigaset driver: fix __must_check warning

This patch to the Siemens Gigaset driver fixes the compile warning
"ignoring return value of 'class_device_create_file', declared with
attribute warn_unused_result" appearing with CONFIG_ENABLE_MUST_CHECK=y in
release 2.6.18-rc1-mm1.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Acked-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/isdn/gigaset/proc.c

@@ -83,5 +83,6 @@ void gigaset_init_dev_sysfs(struct cardstate *cs)
 		return;
 
 	gig_dbg(DEBUG_INIT, "setting up sysfs");
-	class_device_create_file(cs->class, &class_device_attr_cidmode);
+	if (class_device_create_file(cs->class, &class_device_attr_cidmode))
+		dev_err(cs->dev, "could not create sysfs attribute\n");
 }