Ensure client mbedtls_ssl_handshake_step() returns success for HELLO_REQUEST

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 5ea8afa..2d1ffbe 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3257,6 +3257,7 @@
         {
             case MBEDTLS_SSL_HELLO_REQUEST:
                 ssl->state = MBEDTLS_SSL_CLIENT_HELLO;
+                ret = 0;
                 break;
 
             case MBEDTLS_SSL_CLIENT_HELLO: