async: remove the temporary (2.6.29) "async is off by default" code

Now that everyone has been able to test the async code (and it's being used
in the Moblin betas by default), we can enable it by default.
The various fixes needed have gone into 2.6.29 already.

[With an important bugfix from Stefan Richter]
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

kernel/async.c

@@ -49,6 +49,7 @@ asynchronous and synchronous parts of the kernel.
 */
 
 #include <linux/async.h>
+#include <linux/bug.h>
 #include <linux/module.h>
 #include <linux/wait.h>
 #include <linux/sched.h>
@@ -387,20 +388,11 @@ static int async_manager_thread(void *unused)
 
 static int __init async_init(void)
 {
-	if (async_enabled)
-		if (IS_ERR(kthread_run(async_manager_thread, NULL,
-				       "async/mgr")))
-			async_enabled = 0;
-	return 0;
-}
+	async_enabled =
+		!IS_ERR(kthread_run(async_manager_thread, NULL, "async/mgr"));
 
-static int __init setup_async(char *str)
-{
-	async_enabled = 1;
-	return 1;
+	WARN_ON(!async_enabled);
+	return 0;
 }
 
-__setup("fastboot", setup_async);
-
-
 core_initcall(async_init);