[crypto] PSA API: enable native ITS in build system

This commit enables PSA native ITS implementation in the build system
for simulation and test platforms.

Signed-off-by: Łukasz Duda <[email protected]>

src/core/instance/instance.cpp

@@ -303,6 +303,7 @@ Instance::Instance(void)
     , mIsInitialized(false)
     , mId(Random::NonCrypto::GetUint32())
 {
+#if OPENTHREAD_MTD || OPENTHREAD_FTD
 #if OPENTHREAD_CONFIG_MULTIPLE_INSTANCE_ENABLE && OPENTHREAD_CONFIG_PLATFORM_KEY_REFERENCES_ENABLE
 #if OPENTHREAD_CONFIG_MULTIPLE_STATIC_INSTANCE_ENABLE
     mCryptoStorageKeyRefManager.SetKeyRefExtraOffset(Crypto::Storage::KeyRefManager::kKeyRefExtraOffset * GetIdx(this));
@@ -311,6 +312,7 @@ Instance::Instance(void)
        "The `KeyRef` values will be shared across different `Instance` objects"
 #endif
 #endif
+#endif
 }
 
 #if (OPENTHREAD_MTD || OPENTHREAD_FTD) && !OPENTHREAD_CONFIG_HEAP_EXTERNAL_ENABLE