tracing: Fix documentation about disabling options using trace_options

To disable a tracing option using the trace_options file, the option
name needs to be prefixed with 'no', and not suffixed, as the README
states. Fix it.

Link: http://lkml.kernel.org/r/154872690031.47356.5739053380942044586.stgit@srivatsa-ubuntu



Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>