Compiler/TI: Fix depfile generation for C++

In commit v3.11.0-rc1~466^2 (Compiler/TI: Add support for depfile
generation for Ninja, 2017-10-16) the flag for C++ was added in a
variable with a typo in its name.  Fix the spelling.

Issue: #17360

Modules/Compiler/TI-CXX.cmake

@@ -2,7 +2,7 @@ set(CMAKE_LIBRARY_PATH_FLAG "--search_path=")
 set(CMAKE_LINK_LIBRARY_FLAG "--library=")
 set(CMAKE_INCLUDE_FLAG_CXX "--include_path=")
 
-set(CMAKE_DEPFILE_FLAGS_CCX "--preproc_with_compile --preproc_dependency=<DEPFILE>")
+set(CMAKE_DEPFILE_FLAGS_CXX "--preproc_with_compile --preproc_dependency=<DEPFILE>")
 
 set(CMAKE_CXX_CREATE_ASSEMBLY_SOURCE "<CMAKE_CXX_COMPILER> --compile_only --skip_assembler --cpp_file=<SOURCE> <DEFINES> <INCLUDES> <FLAGS> --output_file=<ASSEMBLY_SOURCE>")
 set(CMAKE_CXX_CREATE_PREPROCESSED_SOURCE "<CMAKE_CXX_COMPILER> --preproc_only --cpp_file=<SOURCE> <DEFINES> <INCLUDES> <FLAGS> --output_file=<PREPROCESSED_SOURCE>")