Make the storage configs dependent on the PSA label

This commit makes the storage configurations - setting
MBEDTLS_PSA_CRYPTO_STORAGE_C, MBEDTLS_PSA_CRYPTO_STORAGE_ITS_C and unsetting
MBEDTLS_PSA_CRYPTO_STORAGE_FILE_C - dependent on the PSA label being defined for
the target.

Previously these symbols were always defined for all platforms which could
cause problems for targets that don't yet support PSA.

Author: simonbutcher

features/mbedtls/importer/adjust-config.sh

@@ -145,9 +145,3 @@ conf unset MBEDTLS_PLATFORM_TIME_TYPE_MACRO
 # Reduce the maximal MBEDTLS_MPI_MAX_SIZE to 512 bytes,
 # which should fit RSA 4096 bit keys.
 conf set MBEDTLS_MPI_MAX_SIZE     512
-
-# The following configurations are needed for Mbed Crypto.
-# They are related to the persistent key storage feature.
-conf set MBEDTLS_PSA_CRYPTO_STORAGE_C
-conf set MBEDTLS_PSA_CRYPTO_STORAGE_ITS_C
-conf unset MBEDTLS_PSA_CRYPTO_STORAGE_FILE_C

features/mbedtls/platform/inc/platform_mbed.h

@@ -43,6 +43,15 @@
 #include "mbedtls_device.h"
 #endif
 
+#if defined(TARGET_PSA)
+/* The following configurations are a needed for Mbed Crypto submodule.
+ * They are related to the persistent key storage feature.
+ */
+#define MBEDTLS_PSA_CRYPTO_STORAGE_C
+#define MBEDTLS_PSA_CRYPTO_STORAGE_ITS_C
+#undef MBEDTLS_PSA_CRYPTO_STORAGE_FILE_C
+#endif
+
 /*
  * MBEDTLS_ERR_PLATFORM_HW_FAILED is deprecated and should not be used.
  */