[Bugfix] Avoid some bogus messages RE CUTLASS's revision when building (vllm-project#8702)

Author: tlrmchlsmth

CMakeLists.txt

@@ -192,6 +192,10 @@ set(VLLM_EXT_SRC
 
 if(VLLM_GPU_LANG STREQUAL "CUDA")
   SET(CUTLASS_ENABLE_HEADERS_ONLY ON CACHE BOOL "Enable only the header library")
+
+  # Set CUTLASS_REVISION manually -- its revision detection doesn't work in this case.
+  set(CUTLASS_REVISION "v3.5.1" CACHE STRING "CUTLASS revision to use")
+
   FetchContent_Declare(
         cutlass
         GIT_REPOSITORY https://github.com/nvidia/cutlass.git