feat: implement sm90 megamoe phase5 l2 scatter

deep_gemm/mega/__init__.py

@@ -70,7 +70,8 @@ class SymmBuffer:
              self.l1_arrival_count,
              self.l2_arrival_mask,
              self.token_src_metadata,
-             self.l1_accum_debug) = buffer_views
+             self.l1_accum_debug,
+             self.combine_acts) = buffer_views
         else:
             (self.x, self.x_sf,
              self.topk_idx, self.topk_weights,
@@ -82,6 +83,7 @@ class SymmBuffer:
             self.l2_arrival_mask = None
             self.token_src_metadata = None
             self.l1_accum_debug = None
+            self.combine_acts = None
 
     def destroy(self):
         self.handle = None
@@ -101,6 +103,7 @@ class SymmBuffer:
         self.l2_arrival_mask = None
         self.token_src_metadata = None
         self.l1_accum_debug = None
+        self.combine_acts = None
 
 
 def get_symm_buffer_for_mega_moe(group: dist.ProcessGroup,