Make lldb::endian::InlHostByteOrder() private.

Summary:
Since this is within the lldb namespace, the compiler tries to
export a symbol for it. Unfortunately, since it is inlined, the
symbol is hidden and this results in a mess of warnings when
building on OS X with cmake.

Moving it to the lldb_private namespace eliminates that problem.

Reviewers: clayborg

Subscribers: emaste, lldb-commits

Differential Revision: http://reviews.llvm.org/D14417

llvm-svn: 252396