[ELF][MIPS] Decompose relocation type for N32 / N64 earlier. NFC
[ELF][MIPS] Decompose relocation type for N32 / N64 earlier. NFC

We need to decompose relocation type for N32 / N64 ABI. Let's do it
before any other manipulations with relocation type in the `relocateOne`
routine.

git-svn-id: f6089bf0e6284f307027cef4f64114ee9ebb0424@322860 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/lld,llvm-mirror/lld