API changes
   * Remove HAVEGE module.
     The design of HAVEGE makes it unsuitable for microcontrollers. Platforms
     with a more complex CPU usually have an operating system interface that
     provides better randomness. Instead of HAVEGE, declare OS or hardware RNG
     interfaces with mbedtls_entropy_add_source() and/or use an entropy seed
     file created securely during device provisioning. See
     https://tls.mbed.org/kb/how-to/add-entropy-sources-to-entropy-pool for
     more information.