perf/scripts: Tag syscall_name helper as not yet available

syscall_name() helper, which resolves a syscall arch number to
its name, is not yet available as we first need to implement
event injection for it to work.

Remove it from the documentation or tag its references as
unavailable yet. Once it's implemented, we can just revert
the current patch.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Keiichi KII <k-keiichi@bx.jp.nec.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Documentation/perf-trace-python.txt b/tools/perf/Documentation/perf-trace-python.txt
index 119d5de..a241aca 100644
--- a/tools/perf/Documentation/perf-trace-python.txt
+++ b/tools/perf/Documentation/perf-trace-python.txt
@@ -36,7 +36,8 @@
 
 The syscall-counts script is a simple script, but demonstrates all the
 basic ideas necessary to create a useful script.  Here's an example
-of its output:
+of its output (syscall names are not yet supported, they will appear
+as numbers):
 
 ----
 syscall events:
@@ -270,7 +271,8 @@
 handler called at the end of script processing.
 
 The final script producing the output shown above is shown in its
-entirety below:
+entirety below (syscall_name() helper is not yet available, you can
+only deal with id's for now):
 
 ----
 import os
@@ -617,7 +619,6 @@
   nsecs_nsecs(nsecs) - returns nsecs remainder given nsecs
   nsecs_str(nsecs) - returns printable string in the form secs.nsecs
   avg(total, n) - returns average given a sum and a total number of values
-  syscall_name(id) - returns the syscall name for the specified syscall_nr
 
 SEE ALSO
 --------