Add the CR core clock, which is used by the Secure Engine (SCEG).
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NNiklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Tested-by: NGilad Ben-Yossef <gilad@benyossef.com>