st/mesa: use PIPE_MAX_ATTRIBS as the max number of vertex buffers

Tested-by: Edmondo Tommasina <edmondo.tommasina@gmail.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>

src/mesa/state_tracker/st_atom_array.c

@@ -632,7 +632,7 @@ void st_update_array(struct st_context *st)
    const struct gl_vertex_array **arrays = ctx->Array._DrawArrays;
    const struct st_vertex_program *vp;
    const struct st_vp_variant *vpv;
-   struct pipe_vertex_buffer vbuffer[PIPE_MAX_SHADER_INPUTS];
+   struct pipe_vertex_buffer vbuffer[PIPE_MAX_ATTRIBS];
    struct pipe_vertex_element velements[PIPE_MAX_ATTRIBS];
    unsigned num_vbuffers;