[llvm-branch-commits] [NFCI][ELF][Mips] Refactor MipsGotSection to avoid explicit writes (PR #150730)

[Jessica Clarke via llvm-branch-commits]

https://github.com/jrtc27 created https://github.com/llvm/llvm-project/pull/150730

Splitting the VA / addend calculations between build and writeTo means
having to keep them in sync and duplicating some of the logic. For
everything except "page address" relocations, move all such calculations
into build, mirroring how the normal non-MIPS code in Relocations.cpp
ensures the addend and initial memory contents are set.