Update config.h

Warning for ECJPAKE_C was removed from config.h.
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 650f862..1b0295e 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2606,10 +2606,6 @@
  *
  * Enable the elliptic curve J-PAKE library.
  *
- * \warning This is currently experimental. EC J-PAKE support is based on the
- * Thread v1.0.0 specification; incompatible changes to the specification
- * might still happen.
- *
  * Module:  library/ecjpake.c
  * Caller:
  *