Improve documentation for cap_get_pid and cap_reset_ambient.

- cap_get_pid() add detail about the function argument and return
  value when used across namespaces. Thanks to nemonemo for reporting:

    https://bugzilla.kernel.org/show_bug.cgi?id=215812

- cap_reset_ambient() had some factually incorrect content. Thanks to
  Tinker One for reporting:

    https://bugzilla.kernel.org/show_bug.cgi?id=215910

Signed-off-by: Andrew G. Morgan <morgan@kernel.org>
1 file changed