LU-12333 ptlrpc: Add more flags to DEBUG_REQ_FLAGS macro

LU-12333 ptlrpc: Add more flags to DEBUG_REQ_FLAGS macro

The rq_req_unlinked, rq_reply_unlinked and rq_receiving_reply flags
determine whether a PtlRPC request can transition out of
RQ_PHASE_UNREG_RPC. Add these flags to the DEBUG_REQ_FLAGS macro to
aid in debugging issues where requests are stuck in this unregistering
state.

Test-Parameters: trivial
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: I0b4f424cba70a29c64035ebaccf33fdb954a2db6
Reviewed-on: https://review.whamcloud.com/34949
Reviewed-by: Ann Koehler <amk@cray.com>
Tested-by: Jenkins
Reviewed-by: Amir Shehata <ashehata@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>