tracing: Move a printk out of ftrace_raw_reg_event_foo()

Move the printk from each ftrace_raw_reg_event_foo() to
its caller ftrace_event_enable_disable(). This avoids each
regfunc trace event callbacks to handle a same error report
that can be carried from the caller.

See how much space this saves:

   text    data     bss     dec     hex filename
5345151 1961864 7103260 14410275         dbe223 vmlinux.o.old
5331487 1961864 7103260 14396611         dbacc3 vmlinux.o

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@redhat.com>
LKML-Reference: <4B1DC4AC.802@cn.fujitsu.com>
[start cmdline record before calling regfunc to avoid lost
window of pid to comm resolution]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index b957edd..75289f3 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -325,10 +325,7 @@
 	mutex_lock(&syscall_trace_lock);
 	if (!sys_refcount_enter)
 		ret = register_trace_sys_enter(ftrace_syscall_enter);
-	if (ret) {
-		pr_info("event trace: Could not activate"
-				"syscall entry trace point");
-	} else {
+	if (!ret) {
 		set_bit(num, enabled_enter_syscalls);
 		sys_refcount_enter++;
 	}
@@ -362,10 +359,7 @@
 	mutex_lock(&syscall_trace_lock);
 	if (!sys_refcount_exit)
 		ret = register_trace_sys_exit(ftrace_syscall_exit);
-	if (ret) {
-		pr_info("event trace: Could not activate"
-				"syscall exit trace point");
-	} else {
+	if (!ret) {
 		set_bit(num, enabled_exit_syscalls);
 		sys_refcount_exit++;
 	}