kernel/async.c: fix pr_debug statement

An async_func_t returns void - any errors encountered it has to stash
somewhere for consumers to discover later.

Link: https://lkml.kernel.org/r/20210226124355.2503524-1-linux@rasmusvillemoes.dk
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: Villemoes

kernel/async.c

@@ -124,7 +124,7 @@ static void async_run_entry_fn(struct work_struct *work)
 	if (initcall_debug && system_state < SYSTEM_RUNNING) {
 		rettime = ktime_get();
 		delta = ktime_sub(rettime, calltime);
-		pr_debug("initcall %lli_%pS returned 0 after %lld usecs\n",
+		pr_debug("initcall %lli_%pS returned after %lld usecs\n",
 			(long long)entry->cookie,
 			entry->func,
 			(long long)ktime_to_ns(delta) >> 10);