clk: imx7d: add CAAM clock

Add CAAM clock so that we could use the Cryptographic Acceleration and
Assurance Module (CAAM) hardware block.

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-clk@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>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>