Fix the Linux build issues introduced by r178191.

- All Linux logging channels now use a single global instance of lldb_private::Log, to handle the case of logging during process tear down.
- Also removed a single use of LogSP in FreeBSD and fixed a typo in a comment while reading through ProcessKDPLog.

Reviewed by Daniel Malea.


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@178242 91177308-0d34-0410-b5e6-96231b3b80d8