tools lib traceevent: Man page for page size APIs

Create man pages for libtraceevent APIs:

  tep_get_page_size()
  tep_set_page_size()
Signed-off-by: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/linux-trace-devel/20190503091119.23399-9-tstoyanov@vmware.com
Link: http://lkml.kernel.org/r/20190510200107.218173559@goodmis.orgSigned-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/Documentation/libtraceevent-page_size.txt

+libtraceevent(3)
+================
+
+NAME
+----
+tep_get_page_size, tep_set_page_size - Get / set the size of a memory page on
+the machine, where the trace is generated
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <event-parse.h>*
+
+int *tep_get_page_size*(struct tep_handle pass:[*]_tep_);
+void *tep_set_page_size*(struct tep_handle pass:[*]_tep_, int _page_size_);
+--
+
+DESCRIPTION
+-----------
+The _tep_get_page_size()_ function returns the size of a memory page on
+the machine, where the trace is generated. The _tep_ argument is trace
+event parser context.
+
+The _tep_set_page_size()_ function stores in the _tep_ context the size of a
+memory page on the machine, where the trace is generated.
+The _tep_ argument is trace event parser context.
+The _page_size_ argument is the size of a memory page, in bytes.
+
+RETURN VALUE
+------------
+The _tep_get_page_size()_ function returns size of the memory page, in bytes.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <unistd.h>
+#include <event-parse.h>
+...
+struct tep_handle *tep = tep_alloc();
+...
+	int page_size = getpagesize();
+
+	tep_set_page_size(tep, page_size);
+
+	printf("The page size for this machine is %d\n", tep_get_page_size(tep));
+
+--
+
+FILES
+-----
+[verse]
+--
+*event-parse.h*
+	Header file to include in order to have access to the library APIs.
+*-ltraceevent*
+	Linker switch to add when building a program that uses the library.
+--
+
+SEE ALSO
+--------
+_libtraceevent(3)_, _trace-cmd(1)_
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*.
+*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page.
+--
+REPORTING BUGS
+--------------
+Report bugs to  <linux-trace-devel@vger.kernel.org>
+
+LICENSE
+-------
+libtraceevent is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git