Fix typo in psa config comment
Change "are" to "aren't" to avoid making the comment misleading.
@@ -253,7 +253,7 @@ extern "C" {
#endif /* PSA_WANT_ALG_STREAM_CIPHER */
/* The MBEDTLS_PSA_HAVE_SOFT_KEY_TYPE_* are defined if a key type is selected,
- * but we are configured to accelerate this key type. */
+ * but we aren't configured to accelerate this key type. */
#if defined(PSA_WANT_KEY_TYPE_AES) && !defined(MBEDTLS_PSA_ACCEL_KEY_TYPE_AES)
#define PSA_HAVE_SOFT_KEY_TYPE_AES 1
#endif
