tracing: add exports to use __print_symbolic and __print_flags from a module

A patch to allow the use of __print_symbolic and __print_flags
from a module. This allows the current GFS2 tracing patch to
build.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
LKML-Reference: <1243868015.29604.542.camel@localhost.localdomain>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>