Remove annoying warnings in sgl kernel build (#9905)

sgl-kernel/csrc/gemm/dsv3_fused_a_gemm.cu

@@ -131,6 +131,7 @@ __device__ bool try_wait_barrier(uint64_t* smem_ptr, int phase_bit) {
       : "r"(smem_int_ptr), "r"(phase_bit));
   return static_cast<bool>(wait_complete);
 #endif
+  return false;
 }
 
 // Barrier arrive

sgl-kernel/csrc/gemm/nvfp4_expert_quant.cu

@@ -541,6 +541,11 @@ void quant_impl(
   }
 }
 
+// Avoid redefinition warnings
+#undef CHECK_CONTIGUOUS
+#undef CHECK_TH_CUDA
+#undef CHECK_INPUT
+
 /*Quantization entry for fp4 experts quantization*/
 #define CHECK_TH_CUDA(x, m) TORCH_CHECK(x.is_cuda(), m, "must be a CUDA tensor")
 #define CHECK_CONTIGUOUS(x, m) TORCH_CHECK(x.is_contiguous(), m, "must be contiguous")