[X86]: Correctly sign-extend 16-bit immediate in CALL instruction.

Patch by Matthew Barney. Thanks!

Differential Revision: http://reviews.llvm.org/D9514

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240795 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed