[BugFix] Fix DeepGEMM over-allocating workspace (#28254)

Signed-off-by: Lucas Wilkinson <lwilkins@redhat.com>

vllm/model_executor/layers/fused_moe/deep_gemm_moe.py

@@ -215,7 +215,7 @@ class DeepGemmExperts(mk.FusedMoEPermuteExpertsUnpermute):
         )
         assert M_sum % block_m == 0
 
-        workspace1 = (M_sum, max(N, K))
+        workspace1 = (M_sum, N)
         workspace2 = (M_sum, max(N // 2, K))
         output = (M, K)
         return (workspace1, workspace2, output)