[CodeView] Add pragma push/pop_macro for ARM64_FPSR to enum header

This fixes (one aspect of) compilation of LLDB with MSVC for ARM64.

LLDB source files include intrin.h, and the MSVC intrin.h transitively
includes arm64intr.h, which has an ARM64_FPSR define, which clashes
with the enum declaration.

Differential Revision: https://reviews.llvm.org/D67864

llvm-svn: 372481