perf version: Add man page

Since a new option '--build-options' is created for 'perf version', so
we need to document it.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1522402036-22915-7-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/Documentation/perf-version.txt

@@ -0,0 +1,24 @@
+perf-version(1)
+===============
+
+NAME
+----
+perf-version - display the version of perf binary
+
+SYNOPSIS
+--------
+'perf version' [--build-options]
+
+DESCRIPTION
+-----------
+With no options given, the 'perf version' prints the perf version
+on the standard output.
+
+If the option '--build-options' is given, then the status of
+compiled-in libraries are printed on the standard output.
+
+OPTIONS
+-------
+--build-options::
+        Prints the status of compiled-in libraries on the
+        standard output.