perf trace beauty: Export the pid beautifier for use in more places

perf trace beauty: Export the pid beautifier for use in more places

Now that the beautifiers are being split into multiple source and object
files, we will need more of them exported, do it for the 'pid' one, will
be used to augment the return of some syscalls that may return a 'pid',
such as fcntl(fd, F_GETOWN).

Will also be used for fcntl(fd, F_SETOWN, pid).

Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>