MD no longer depends on a built-in hash

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index d889e7e..bf88f61 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -2644,7 +2644,8 @@
  *
  * Requires: one of: MBEDTLS_MD5_C, MBEDTLS_RIPEMD160_C, MBEDTLS_SHA1_C,
  *                   MBEDTLS_SHA224_C, MBEDTLS_SHA256_C, MBEDTLS_SHA384_C,
- *                   MBEDTLS_SHA512_C.
+ *                   MBEDTLS_SHA512_C, or MBEDTLS_PSA_CRYPTO_C with a least
+ *                   one hash.
  * Module:  library/md.c
  * Caller:  library/constant_time.c
  *          library/ecdsa.c