disable verbose output for jitify_preprocess (#7886)

Remove `-v` option from `jitify_preprocess` invocation to reduce "Found #include ..."-like output during builds.

Authors:
  - Christopher Harris (https://github.com/cwharris)

Approvers:
  - Keith Kraus (https://github.com/kkraus14)

URL: #7886

cpp/cmake/Modules/JitifyPreprocessKernels.cmake

@@ -38,7 +38,6 @@ function(jit_preprocess_files)
                            COMMAND ${CMAKE_COMMAND} -E make_directory "${jit_output_directory}"
                            COMMAND jitify_preprocess ${ARG_FILE}
                                     -o ${CUDF_GENERATED_INCLUDE_DIR}/include/jit_preprocessed_files
-                                    -v
                                     -i
                                     -m
                                     -std=c++14