[Hackathon 7th] 修复 `vctk` 的 `ernie_sat` 训练时出现的类型提升问题 (#3943)

* [Fix] vctk type promotion

* [Fix] type promotion

paddlespeech/t2s/modules/losses.py

@@ -1114,6 +1114,7 @@ class MLMLoss(nn.Layer):
                     paddle.reshape(after_outs, (-1, self.odim)),
                     paddle.reshape(xs_pad, (-1, self.odim))),
                 axis=-1)
+        mlm_loss_pos = (mlm_loss_pos).astype(loss.dtype)
         mlm_loss = paddle.sum((loss * paddle.reshape(
             mlm_loss_pos,
             [-1]).astype(loss.dtype))) / paddle.sum((mlm_loss_pos) + 1e-10)