init/main.c: don't use pr_debug()

Pertially revert commit ea676e84 ("init/main.c: convert to
pr_foo()").

Unbeknownst to me, pr_debug() is different from the other pr_foo()
levels: pr_debug() is a no-op when DEBUG is not defined.

Happily, init/main.c does have a #define DEBUG so we didn't break
initcall_debug.  But the functioning of initcall_debug should not be
dependent upon the presence of that #define DEBUG.
Reported-by: Russell King <rmk@arm.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

init/main.c

@@ -671,13 +671,13 @@ static int __init_or_module do_one_initcall_debug(initcall_t fn)
 	unsigned long long duration;
 	int ret;
 
-	pr_debug("calling  %pF @ %i\n", fn, task_pid_nr(current));
+	printk(KERN_DEBUG "calling  %pF @ %i\n", fn, task_pid_nr(current));
 	calltime = ktime_get();
 	ret = fn();
 	rettime = ktime_get();
 	delta = ktime_sub(rettime, calltime);
 	duration = (unsigned long long) ktime_to_ns(delta) >> 10;
-	pr_debug("initcall %pF returned %d after %lld usecs\n",
+	printk(KERN_DEBUG "initcall %pF returned %d after %lld usecs\n",
 		 fn, ret, duration);
 
 	return ret;