ftrace: enable format arguments checking

Impact: broaden gcc printf format checks for ftrace_printk()

format arguments checking for ftrace_printk() is __printf(1, 2),
not __printf(1, 0).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/ftrace.h

@@ -303,7 +303,7 @@ extern void ftrace_dump(void);
 static inline void
 ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) { }
 static inline int
-ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0)));
+ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
 
 static inline void tracing_start(void) { }
 static inline void tracing_stop(void) { }