Crypto: Reduce diverging PSA Crypto headers between TF-M and Mbed TLS

Reduce divergence between PSA Crypto headers available in TF-M and
Mbed TLS.

* Consistently use mbedtls_svc_key_id_t for psa_key_id_t in the headers
* Concentrate IMPDEF behaviour in crypto_struct and crypto_platform
* Make sure the same config file is used for client and server views,
  i.e. make sure that ENCODES_OWNER config define is passed in a
  dedicated compile switch privately to the crypto service
* Add \emptydescription for Doxygen when required
* clean up the psa_crypto_config cmake target

Signed-off-by: Antonio de Angelis <antonio.deangelis@arm.com>
Change-Id: Ia65c9d267ac9dc0441ea484408c5501c1558e580
diff --git a/interface/include/psa/crypto_platform.h b/interface/include/psa/crypto_platform.h
new file mode 100644
index 0000000..e49438a
--- /dev/null
+++ b/interface/include/psa/crypto_platform.h
@@ -0,0 +1,35 @@
+
+/*
+ * Copyright (c) 2023, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ */
+/**
+ * \file psa/crypto_platform.h
+ *
+ * \brief PSA cryptography module: TF-M platform definitions
+ *
+ * \note This file may not be included directly. Applications must
+ * include psa/crypto.h.
+ *
+ * This file contains platform-dependent type definitions.
+ *
+ * In implementations with isolation between the application and the
+ * cryptography module, implementers should take care to ensure that
+ * the definitions that are exposed to applications match what the
+ * module implements.
+ */
+
+#ifndef PSA_CRYPTO_PLATFORM_H
+#define PSA_CRYPTO_PLATFORM_H
+
+/* PSA requires several types which C99 provides in stdint.h. */
+#include <stdint.h>
+
+/* No particular platform definition is currently required for the
+ * TF-M client view of the PSA Crytpo APIs, but we keep this header
+ * available for reference and future compatibility
+ */
+
+#endif /* PSA_CRYPTO_PLATFORM_H */