NFSD: Remove spurious cb_setup_err tracepoint

[ Upstream commit 9f57c606 ]

This path is not really an error path, so the tracepoint I added
there is just noise.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Stable-dep-of: 3bc8edc9 ("nfsd: under NFSv4.1, fix double svc_xprt_put on rpc_create failure")
Signed-off-by: Sasha Levin <sashal@kernel.org>