NFSD: Fix a thinko introduced by recent trace point changes

The fixed commit erroneously removed a call to nfsd_end_grace(),
which makes calls to write_v4_end_grace() a no-op.

Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202308241229.68396422-oliver.sang@intel.com


Fixes: 39d432fc ("NFSD: trace nfsctl operations")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>