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>

arch/arm/mach-imx/mx7/soc.c

@@ -17,6 +17,7 @@
 #include <asm/arch/crm_regs.h>
 #include <dm.h>
 #include <imx_thermal.h>
+#include <fsl_sec.h>
 
 #if defined(CONFIG_IMX_THERMAL)
 static const struct imx_thermal_plat imx7_thermal_plat = {
@@ -191,6 +192,10 @@ int arch_misc_init(void)
 		env_set("soc", "imx7s");
 #endif
 
+#ifdef CONFIG_FSL_CAAM
+	sec_init();
+#endif
+
 	return 0;
 }
 #endif