[ELF] Factor out the code creates a Reference for the specified symbol
and relocation entry into the two virtual functions.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@203408 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Create ELF object reader for MIPS target.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@203409 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Fix addendum reading for R_MIPS_HI16 / R_MIPS_LO16 relocations.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@203410 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Fix addendum reading for R_MIPS_32 relocation.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@203411 91177308-0d34-0410-b5e6-96231b3b80d8
[Mips] Fix addendum reading for R_MIPS_26 relocation.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@203412 91177308-0d34-0410-b5e6-96231b3b80d8