kprobes: Init kprobes in early_initcall

Init kprobes feature in early_initcall as same as jump_label and
dynamic_debug does, so that we can use kprobes events in earlier
boot stage.

Link: https://lkml.kernel.org/r/159974151897.478751.8342374158615496628.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

kernel/kprobes.c

@@ -2529,7 +2529,7 @@ static int __init init_kprobes(void)
 		init_test_probes();
 	return err;
 }
-subsys_initcall(init_kprobes);
+early_initcall(init_kprobes);
 
 #ifdef CONFIG_DEBUG_FS
 static void report_probe(struct seq_file *pi, struct kprobe *p,