Make use of PSA crypto hash if MBEDTLS_MD_C isn't defined

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

include/mbedtls/check_config.h

@@ -108,7 +108,8 @@
 #endif
 
 #if defined(MBEDTLS_ECJPAKE_C) &&           \
-    ( !defined(MBEDTLS_ECP_C) || !defined(MBEDTLS_MD_C) )
+    ( !defined(MBEDTLS_ECP_C) ||            \
+      !( defined(MBEDTLS_MD_C) || defined(MBEDTLS_PSA_CRYPTO_C) ) )
 #error "MBEDTLS_ECJPAKE_C defined, but not all prerequisites"
 #endif
 

include/mbedtls/mbedtls_config.h

@@ -2330,6 +2330,9 @@
  *      ECJPAKE
  *
  * Requires: MBEDTLS_ECP_C, MBEDTLS_MD_C
+ *
+ * \warning If building without MBEDTLS_MD_C, you must call psa_crypto_init()
+ * before doing any EC J-PAKE operations.
  */
 #define MBEDTLS_ECJPAKE_C