crypto/fsl: add RNG support

Register the random number generator with the rng subsystem in u-boot.
This way it can be used by EFI as well as for the 'rng' command.

Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/drivers/crypto/fsl/Kconfig b/drivers/crypto/fsl/Kconfig
index 181a1e5..5ed6140 100644
--- a/drivers/crypto/fsl/Kconfig
+++ b/drivers/crypto/fsl/Kconfig
@@ -45,3 +45,17 @@
 
 config SYS_FSL_SEC_LE
 	bool "Little-endian access to Freescale Secure Boot"
+
+if FSL_CAAM
+
+config FSL_CAAM_RNG
+	bool "Enable Random Number Generator support"
+	depends on DM_RNG
+	default y
+	help
+	  Enable support for the hardware based random number generator
+	  module of the CAAM. The random data is fetched from the DRGB
+	  using the prediction resistance flag which means the DRGB is
+	  reseeded from the TRNG every time random data is generated.
+
+endif