ftrace: fix setting of pos in read_pipe

In resetting the iterator in read_pipe, the reset of pos was
postitioned in the wrong location with respect to the memset
operation. The current code sets pos, incorrectly, to zero.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/trace/trace.c

@@ -2455,10 +2455,10 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
 		cnt = PAGE_SIZE - 1;
 
 	/* reset all but tr, trace, and overruns */
-	iter->pos = -1;
 	memset(&iter->seq, 0,
 	       sizeof(struct trace_iterator) -
 	       offsetof(struct trace_iterator, seq));
+	iter->pos = -1;
 
 	/*
 	 * We need to stop all tracing on all CPUS to read the