[FRONTEND] Fix pytorch warning. (#560)

UserWarning: __floordiv__ is deprecated, and its behavior will change in a future version of pytorch. It currently rounds toward 0 (like the 'trunc' function NOT 'floor'). This results in incorrect rounding for negative values. To keep the current behavior, use torch.div(a, b, rounding_mode='trunc').

python/bench/bench_matmul.py

@@ -5,7 +5,7 @@ import triton
 
 def rounded_linspace(low, high, steps, div):
     ret = torch.linspace(low, high, steps)
-    ret = (ret.int() + div - 1) // div * div
+    ret = torch.div(ret.int() + div - 1, div, rounding_mode='trunc') * div
     ret = torch.unique(ret)
     return list(map(int, ret))