[MC] Constify MCELF::GetVisibility and MCELF::getOther

These two routines didn't take a "const MCSymbolData &SD"
like the other MCELF::Get routines for some reason ...



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212834 91177308-0d34-0410-b5e6-96231b3b80d8