ppc/km/tegr1: support second localbus clock signal

On kmtegr1 we have to specify the second localbus clock signal also
instead of using the default for our ppc 8309 boards.

Signed-off-by: Holger Brunck <holger.brunck@ch.abb.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
CC: Priyanka Jain <priyanka.jain@nxp.com>
CC: Valentin Longchamp <valentin.longchamp@ch.abb.com>