[WIN] Fix C7555 build error

C7555: use of designated initializers requires at least '/std:c++20'

Signed-off-by: Whitney Tsang <[email protected]>

Author: whitneywhtsang

lib/Dialect/TritonGPU/Transforms/Pipeliner/LowerLoops.cpp

@@ -592,8 +592,8 @@ scf::ForOp lowerLoads(scf::ForOp forOp, CoarseSchedule &schedule) {
           // Allocate additional buffer required by the wgmma pipelining.
           stageDiff += 1;
         }
-        asyncLoads[&op] = {.stageDiff = stageDiff,
-                           .sharedEncoding = sharedEncoding};
+        asyncLoads[&op] =
+            AsyncLoad{stageDiff, nullptr, nullptr, nullptr, sharedEncoding};
       } else if (stageDiff > 1) {
         // Distance-1 loads can in most cases be pipelined in registers without
         // any performance degradation, as the schedule will usually reorder the