Fix: Ensure DTW cost tensor is on the same device as input tensor (#2561)

Co-authored-by: Jong Wook Kim <jongwook@openai.com>

whisper/timing.py

@@ -117,7 +117,7 @@ def dtw_cuda(x, BLOCK_SIZE=1024):
     x_skew = x_skew.T.contiguous()
     cost = torch.ones(N + M + 2, M + 2) * np.inf
     cost[0, 0] = 0
-    cost = cost.cuda()
+    cost = cost.to(x.device)
     trace = torch.zeros_like(cost, dtype=torch.int32)
 
     dtw_kernel[(1,)](