[mips] Fix off by one issue when applying a fixup.

The branch offset for a R_MIPS_PC16 relocation is indeed a 16-bit signed
immediate.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197506 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed