Add the 'M' status flag to indicate those proceses or threads which

Add the 'M' status flag to indicate those proceses or threads which
are NOT holding the MP lock (the Big Giant Lock).  Typically: user processes
running in userland, the idle threads, and certain other kernel threads
as we begin to unwind the MP lock from the system.  At some point in
the future to avoid clutter when the majority of threads are running
without Giant, we will change 'M' to 'G' where 'G' will indicate when the
MP lock is held.