Replace MBEDTLS_MD_CAN_SHA384 with PSA_WANT_ALG_SHA_384

Signed-off-by: Elena Uziunaite <elena.uziunaite@arm.com>
diff --git a/tests/include/test/ssl_helpers.h b/tests/include/test/ssl_helpers.h
index 77f85c4..00e45c3 100644
--- a/tests/include/test/ssl_helpers.h
+++ b/tests/include/test/ssl_helpers.h
@@ -40,7 +40,7 @@
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
 #if defined(MBEDTLS_SSL_HAVE_AES)
 #if defined(MBEDTLS_SSL_HAVE_GCM)
-#if defined(MBEDTLS_MD_CAN_SHA384)
+#if defined(PSA_WANT_ALG_SHA_384)
 #define MBEDTLS_TEST_HAS_TLS1_3_AES_256_GCM_SHA384
 #endif
 #if defined(MBEDTLS_MD_CAN_SHA256)