Simplify the templating a bit.

Since we only ever instantiate with a type that is a MachOType instantiation,
we don't need to pass template argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179178 91177308-0d34-0410-b5e6-96231b3b80d8
Template MachOObjectFile over endianness too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179179 91177308-0d34-0410-b5e6-96231b3b80d8