ARM: dts: imx7s: add CAAM device node

Add CAAM device node to the i.MX7s device tree.

Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: devicetree@vger.kernel.org
Cc: "Horia Geantă" <horia.geanta@nxp.com>
Cc: Aymen Sghaier <aymen.sghaier@nxp.com>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>