add gemma vision encoder

ml/backend/ggml/ggml.go

@@ -947,6 +947,13 @@ func (t *Tensor) Conv2D(ctx ml.Context, t2 ml.Tensor, s0, s1, p0, p1, d0, d1 int
 	}
 }
 
+func (t *Tensor) AvgPool1D(ctx ml.Context, k, s, p int) ml.Tensor {
+	return &Tensor{
+		b: t.b,
+		t: C.ggml_pool_1d(ctx.(*Context).ctx, t.t, C.GGML_OP_POOL_AVG, C.int(k), C.int(s), C.int(p)),
+	}
+}
+
 func (t *Tensor) ScaledDotProductAttention(ctx ml.Context, key, value, mask ml.Tensor, scale float64) ml.Tensor {
 	var kqMask *C.struct_ggml_tensor
 	if mask != nil {