tracing: update Documentation on max preds limit

Preds is no longer stored in a fixed-size stack. The max preds now
is 2^14, and is way more than enough, so don't bother to document it.

Link: http://lkml.kernel.org/r/4EAA5E54.1080102@cn.fujitsu.com

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Documentation/trace/events.txt

@@ -191,8 +191,6 @@ And for string fields they are:
 
 Currently, only exact string matches are supported.
 
-Currently, the maximum number of predicates in a filter is 16.
-
 5.2 Setting filters
 -------------------