NFSD: Fix infinite loop in layout state revocation

NFSD: Fix infinite loop in layout state revocation

find_one_sb_stid() skips stids whose sc_status is non-zero, but the
SC_TYPE_LAYOUT case in nfsd4_revoke_states() never sets sc_status
before calling nfsd4_close_layout(). The retry loop therefore finds
the same layout stid on every iteration, hanging the revoker
indefinitely.

Fixes: 1e33e1414bec ("nfsd: allow layout state to be admin-revoked.")
Reported-by: Dai Ngo <dai.ngo@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>