[nrf fromlist] secure_storage: use dynamic PSA key slots in samples/tests

Use dynamic key slots for better compatibility as static ones are a new
feature that not all PSA Crypto implementations support.

Explicitly enable CONFIG_MBEDTLS_ENABLE_HEAP to ensure that Mbed TLS uses
heap for the PSA key slots (instead of failing at runtime).
This will turn off CONFIG_MBEDTLS_PSA_STATIC_KEY_SLOTS, making the
implementation default to dynamic key slots.

Signed-off-by: Tomi Fontanilles <[email protected]>

Upstream PR #: 85735

(cherry picked from commit ffb764773ffde41783a16faecfedd2cb481bae8a)
Signed-off-by: Tomi Fontanilles <[email protected]>

Author: tomi-font

samples/psa/persistent_key/overlay-secure_storage.conf

@@ -2,6 +2,8 @@
 
 CONFIG_MBEDTLS=y
 CONFIG_MBEDTLS_PSA_CRYPTO_C=y
+CONFIG_MBEDTLS_ENABLE_HEAP=y
+CONFIG_MBEDTLS_HEAP_SIZE=1024
 
 # The default stack size (1024) is not enough for the PSA Crypto core.
 # On top of that, the ITS implementation uses the stack for buffers.

tests/subsys/secure_storage/psa/crypto/overlay-secure_storage.conf

@@ -8,6 +8,8 @@ CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG_ALLOW_NON_CSPRNG=y
 # PSA Crypto needs some heap, but MINIMAL_LIBC has none by default.
 CONFIG_COMMON_LIBC_MALLOC_ARENA_SIZE=2048
 CONFIG_MBEDTLS_PSA_CRYPTO_C=y
+CONFIG_MBEDTLS_ENABLE_HEAP=y
+CONFIG_MBEDTLS_HEAP_SIZE=1024
 
 CONFIG_SECURE_STORAGE=y
 # For testing isolation between the different callers of the ITS.