Fuse two kernels of hidden states padding into quantization kernel (#9005)

Co-authored-by: Qiaolin-Yu <liin1211@outlook.com>

python/sglang/srt/layers/quantization/mxfp4.py

@@ -570,8 +570,11 @@ class Mxfp4MoEMethod(FusedMoEMethodBase):
     ) -> torch.Tensor:
         if self.use_flashinfer:
             # Based on profiling results, we need to quantize x to mxfp8 here to achieve better performance
-            x_quant, x_scale = mxfp8_quantize(x, False)  # to mxfp8
+            x_quant, x_scale = mxfp8_quantize(
+                x, False, alignment=self.hidden_size
+            )  # to mxfp8
             x_scale = x_scale.view(torch.float8_e4m3fn).reshape(-1)
+            assert x_quant.shape[-1] == self.hidden_size
 
             top_k, router_logits = topk_output