[X86] Add a Requires<[In64BitMode]> to FARJMP64

Otherwise we can try to assemble it in 32-bit mode and throw an assert in the encoder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@331161 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed