CMake: don't enforce std channels

According to the CMake documentation, this is intended for file
redirection. Since we don't redirect to files, but basically enforce
std channels, this conflicts with any existing redirection set up when
CMake is invoked. As a result the messages are lost.

Signed-off-by: Axel Heider <axel.heider@hensoldt-cyber.de>

config.cmake

@@ -168,9 +168,6 @@ if(DEFINED KernelDTSList AND (NOT "${KernelDTSList}" STREQUAL ""))
                 "${device_dest}" --hardware-config "${config_file}" --hardware-schema
                 "${config_schema}" --yaml --yaml-out "${platform_yaml}" --arch "${KernelArch}"
                 --addrspace-max "${KernelPaddrUserTop}"
-            INPUT_FILE /dev/stdin
-            OUTPUT_FILE /dev/stdout
-            ERROR_FILE /dev/stderr
             RESULT_VARIABLE error
         )
         if(error)