fix deprecated tf method (#14671)

tf.matrix_band_part -> tf.linalg.band_part

src/transformers/models/xlnet/modeling_tf_xlnet.py

@@ -497,12 +497,12 @@ class TFXLNetMainLayer(tf.keras.layers.Layer):
 
         """
         attn_mask = tf.ones([qlen, qlen])
-        mask_u = tf.matrix_band_part(attn_mask, 0, -1)
-        mask_dia = tf.matrix_band_part(attn_mask, 0, 0)
+        mask_u = tf.linalg.band_part(attn_mask, 0, -1)
+        mask_dia = tf.linalg.band_part(attn_mask, 0, 0)
         attn_mask_pad = tf.zeros([qlen, mlen])
         ret = tf.concat([attn_mask_pad, mask_u - mask_dia], 1)
         if self.same_length:
-            mask_l = tf.matrix_band_part(attn_mask, -1, 0)
+            mask_l = tf.linalg.band_part(attn_mask, -1, 0)
             ret = tf.concat([ret[:, :qlen] + mask_l - mask_dia, ret[:, qlen:]], 1)
         return ret