In commit bd827f98 (Use COFF file header header for architecture
detection, 2013-08-05) the MSVC_<lang>_ARCHITECTURE_ID value computed by
CMakeDetermineCompilerId.cmake changed for WinCE architectures to be the
exact architecture read from the PE header.  Fix platform preprocessor
definitions in Modules/Platform/Windows-MSVC.cmake to correspond to the
architecture family (ARM or SHx) instead of the specific architecture.