Platform: Enable CC312 integration

Add platform cc312 directory. Add cmake for building. Add utility
functions to platform dir. Add supplementary mbedtls config file. Add
redirect for logging (GNUARM only).

Change-Id: I9fe7632c0db0a2ef5ee9756a0e743508a6b19559
Signed-off-by: Raef Coles <raef.coles@arm.com>
diff --git a/docs/user_guides/tfm_build_instruction.rst b/docs/user_guides/tfm_build_instruction.rst
index 04de8a5..70c5358 100644
--- a/docs/user_guides/tfm_build_instruction.rst
+++ b/docs/user_guides/tfm_build_instruction.rst
@@ -224,7 +224,9 @@
          - ``Relwithdebinfo``
          - ``Minsizerel``
    * - -DMBEDCRYPTO_DEBUG=<ON|OFF>
-     - Enables debug symbols for Mbed Crypto library.
+     - Enables debug symbols for Mbed Crypto library. If a cryptographic
+       accelerator is enabled then this will also enable debug symbols and
+       logging for any accelerator libraries.
    * - -DBUILD_DWARF_VERSION=<dwarf version>
      - Configures DWARF version.
        The possible values are: