Before this patch, with MSVC I was seeing:
```
[304/334] Building CXX object tools\lld\ELF\CMakeFiles\lldELF.dir\InputFiles.cpp.obj
C:\git\llvm-project\lld\ELF\InputFiles.h(327): warning C4661: 'void lld:🧝:ObjFile<llvm::object::ELF32LE>::importCmseSymbols(void)': no suitable definition provided for explicit template instantiation request
C:\git\llvm-project\lld\ELF\InputFiles.h(291): note: see declaration of 'lld:🧝:ObjFile<llvm::object::ELF32LE>::importCmseSymbols'
C:\git\llvm-project\lld\ELF\InputFiles.h(327): warning C4661: 'void lld:🧝:ObjFile<llvm::object::ELF32LE>::redirectCmseSymbols(void)': no suitable definition provided for explicit template instantiation request
C:\git\llvm-project\lld\ELF\InputFiles.h(292): note: see declaration of 'lld:🧝:ObjFile<llvm::object::ELF32LE>::redirectCmseSymbols'
```
This patch removes `redirectCmseSymbols` which is not defined. And it
imports `importCmseSymbols` in InputFiles.cpp, because it is already
explicitly instantiated in ARM.cpp.
a2ef046a2d