imx: mx7: run sec_init for CAAM RNG

imx: mx7: run sec_init for CAAM RNG

This patch adds a sec_init call into arch_misc_init(). Doing so in
conjunction with the patch "drivers/crypto/fsl: assign job-rings to
non-TrustZone" enables use of the CAAM in Linux when OPTEE/TrustZone is
active.

u-boot will initialise the RNG and assign ownership of the job-ring
registers to a non-TrustZone context. With recent changes by Lukas Auer to
fully initialize the RNG in sec_init() this means that u-boot will hand-off
the CAAM in a state that Linux then can use the CAAM without touching the
reserved DECO registers.

This change is safe both for the OPTEE/TrustZone boot path and the regular
non-OPTEE/TrustZone boot path.

Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Marco Franchi <marco.franchi@nxp.com>
Cc: Vanessa Maegima <vanessa.maegima@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Tested-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>