kthread: silence bogus section mismatch warning

WARNING: kernel/built-in.o(.text+0x16910): Section mismatch:
reference to .init.text: (between 'kthreadd' and 'init_waitqueue_head')

comes because kernel/kthread.c:kthreadd() is not __init but calls
kthreadd_setup() which is __init. But this is ok, because kthreadd_setup()
is only ever called at init time, and then kthreadd() proceeds into its
"for (;;)" loop. We could mark kthreadd __init_refok, but kthreadd_setup()
with just one callsite and 4 lines in it (it's been that small since
10ab825bdef8df51) doesn't need to be a separate function at all -- so let's
just move those four lines at beginning of kthreadd() itself.

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/kthread.c

@@ -214,23 +214,15 @@ int kthread_stop(struct task_struct *k)
 }
 EXPORT_SYMBOL(kthread_stop);
 
-
-static noinline __init_refok void kthreadd_setup(void)
+int kthreadd(void *unused)
 {
 	struct task_struct *tsk = current;
 
+	/* Setup a clean context for our children to inherit. */
 	set_task_comm(tsk, "kthreadd");
-
 	ignore_signals(tsk);
-
 	set_user_nice(tsk, -5);
 	set_cpus_allowed(tsk, CPU_MASK_ALL);
-}
-
-int kthreadd(void *unused)
-{
-	/* Setup a clean context for our children to inherit. */
-	kthreadd_setup();
 
 	current->flags |= PF_NOFREEZE;