Revert "y2038: rusage: use __kernel_old_timeval"

This reverts commit d5e38d6b, which
was commit bdd565f817a74b9e30edec108f7cb1dbc762b8a6 upstream.  It
broke the build for alpha and that can't be fixed without backporting
other more intrusive y2038 changes.

This was not a completely clean revert as the affected code in
getrusage() was moved by subsequent changes.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>