[git-clang-format] Process CUDA header files

Clang supports compiling CUDA source files,
CUDA header files may contain CUDA specific code
that is why they have special extension, which
can be recognized by nvcc (CUDA compiler driver)
as CUDA source file.
Format them by default as well.

Reviewed By: MyDeveloperDay

Patch By: tomilov

Differential Revision: https://reviews.llvm.org/D90780