Uboot RNG Driver using Data Co-processor

This commit introduces Random number generator to uboot. It uses DCP
driver for number generation.
RNG driver can be invoked by using below command on uboot prompt:-
           rng <number of bytes>

Signed-off-by: Kshitiz Varshney <kshitiz.varshney@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/crypto/fsl/Kconfig b/drivers/crypto/fsl/Kconfig
index b04c701..91a51cc 100644
--- a/drivers/crypto/fsl/Kconfig
+++ b/drivers/crypto/fsl/Kconfig
@@ -73,3 +73,13 @@
 	  reseeded from the TRNG every time random data is generated.
 
 endif
+
+config FSL_DCP_RNG
+	bool "Enable Random Number Generator support"
+	depends on DM_RNG
+	default n
+	help
+	  Enable support for the hardware based random number generator
+	  module of the DCP. It uses the True Random Number Generator (TRNG)
+	  and a Pseudo-Random Number Generator (PRNG) to achieve a true
+	  randomness and cryptographic strength.