renderer: fix memory leak in vertex elements state create

Reported-by: Li Qiang
Free the vertex array in error path.
This was introduced by this commit:
renderer: fix heap overflow in vertex elements state create.

I rewrote the code to not require the allocation in the first
place if we have an error, seems nicer.

Signed-off-by: Dave Airlie <airlied@redhat.com>

src/vrend_renderer.c

@@ -1648,18 +1648,19 @@ int vrend_create_vertex_elements_state(struct vrend_context *ctx,
                                        unsigned num_elements,
                                        const struct pipe_vertex_element *elements)
 {
-   struct vrend_vertex_element_array *v = CALLOC_STRUCT(vrend_vertex_element_array);
+   struct vrend_vertex_element_array *v;
    const struct util_format_description *desc;
    GLenum type;
    int i;
    uint32_t ret_handle;
 
-   if (!v)
-      return ENOMEM;
-
    if (num_elements > PIPE_MAX_ATTRIBS)
       return EINVAL;
 
+   v = CALLOC_STRUCT(vrend_vertex_element_array);
+   if (!v)
+      return ENOMEM;
+
    v->count = num_elements;
    for (i = 0; i < num_elements; i++) {
       memcpy(&v->elements[i].base, &elements[i], sizeof(struct pipe_vertex_element));