CTR_DRBG: Document the security strength and SP 800-90A compliance
CTR_DRBG: Document the security strength and SP 800-90A compliance

Document that a derivation function is used.

Document the security strength of the DRBG depending on the
compile-time configuration and how it is set up. In particular,
document how the nonce specified in SP 800-90A is set.

Mention how to link the ctr_drbg module with the entropy module.

NXPmicro/mbedtls,ARMmbed/mbedtls,ARMmbed/mbedtls,NXPmicro/mbedtls,NXPmicro/mbedtls,ARMmbed/mbedtls,NXPmicro/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls,ARMmbed/mbedtls,Mbed-TLS/mbedtls,Mbed-TLS/mbedtls