Remove MBEDTLS_GCM_ALT

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/tests/include/test/psa_crypto_helpers.h b/tests/include/test/psa_crypto_helpers.h
index 5bab8e4..062beaf 100644
--- a/tests/include/test/psa_crypto_helpers.h
+++ b/tests/include/test/psa_crypto_helpers.h
@@ -293,8 +293,7 @@
  *  \param  alg             The AEAD algorithm.
  *  \param  nonce_length    The nonce length in number of bytes.
  */
-#if defined(MBEDTLS_GCM_ALT) || \
-    defined(MBEDTLS_PSA_ACCEL_ALG_GCM)
+#if defined(MBEDTLS_PSA_ACCEL_ALG_GCM)
 #define MBEDTLS_TEST_HAVE_ALT_GCM  1
 #else
 #define MBEDTLS_TEST_HAVE_ALT_GCM  0