[LLDB][MIPS] Use qfThreadID if qC packet is not supported by target

    SUMMARY:
    The patch uses qfThreadID to get the thread IDs if qC packet is not supported by target.
    
    Reviewers: jingham, clayborg
    Subscribers: nitesh.jain, mohit.bhakkad, sagar, bhushan and lldb-commits
    Differential Revision: http://reviews.llvm.org/D11519

llvm-svn: 244866