Add extra MBEDTLS_PSA_CRYPTO_C guard for header

Do not include psa_memory_poisoning_wrappers.h unless
MBEDTLS_PSA_CRYPTO_C is set.

Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/tests/src/helpers.c b/tests/src/helpers.c
index 1c58fae..843a9d4 100644
--- a/tests/src/helpers.c
+++ b/tests/src/helpers.c
@@ -13,7 +13,7 @@
 #include <test/psa_crypto_helpers.h>
 #endif
 
-#if defined(MBEDTLS_TEST_HOOKS)
+#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_PSA_CRYPTO_C)
 #include <test/psa_memory_poisoning_wrappers.h>
 #endif