tracing/syscalls: Fix typo in SYSCALL_DEFINE0

The struct syscall_metadata variable name in SYSCALL_DEFINE0
should be __syscall_meta__##sname instead of __syscall_meta_##sname
to match the name that is in SYSCALL_DEFINE1/2/3/4/5/6.

This error causes event_enter_##sname->data to point to the wrong
location, which causes syscalls which are defined by SYSCALL_DEFINE0()
not to be traced.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D2E.1010807@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

include/linux/syscalls.h

@@ -195,7 +195,7 @@ struct perf_event_attr;
 	static const struct syscall_metadata __used		\
 	  __attribute__((__aligned__(4)))			\
 	  __attribute__((section("__syscalls_metadata")))	\
-	  __syscall_meta_##sname = {				\
+	  __syscall_meta__##sname = {				\
 		.name 		= "sys_"#sname,			\
 		.nb_args 	= 0,				\
 		.enter_event	= &event_enter__##sname,	\