Doc: pps: Fix file name in pps.txt

This patch fix a file name of example code.

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
1 file changed