trace-cmd: Build and install doc by default
trace-cmd: Build and install doc by default

I have been informed that documentation (man pages) should be installed
by default and not just separate.

Reported-by: Dave Chinner <4d9e23a041ac966f5316a7481300d4ae12e806fe@redhat.com>
Signed-off-by: Steven Rostedt <43232e92d70cc7aa53504ad0397085ee47bad87f@goodmis.org>

bigzz/trace-cmd,bigzz/trace-cmd