Minor fixes to parameter validation in ECDH module
diff --git a/library/ecdh.c b/library/ecdh.c
index 37927f7..da95c60 100644
--- a/library/ecdh.c
+++ b/library/ecdh.c
@@ -64,10 +64,6 @@
                     mbedtls_ecp_restart_ctx *rs_ctx )
 {
     int ret;
-    ECDH_VALIDATE_RET( grp != NULL );
-    ECDH_VALIDATE_RET( d != NULL );
-    ECDH_VALIDATE_RET( Q != NULL );
-    ECDH_VALIDATE_RET( f_rng != NULL );
 
     /* If multiplication is in progress, we already generated a privkey */
 #if defined(MBEDTLS_ECP_RESTARTABLE)
@@ -513,6 +509,7 @@
     ECDH_VALIDATE_RET( ctx != NULL );
     ECDH_VALIDATE_RET( olen != NULL );
     ECDH_VALIDATE_RET( buf != NULL );
+    ECDH_VALIDATE_RET( f_rng != NULL );
 
 #if defined(MBEDTLS_ECP_RESTARTABLE)
     restart_enabled = ctx->restart_enabled;