NFSD: Fix nfsd_breaker_owns_lease() return values

stable inclusion
from stable-v5.10.110
commit d91d1e681c999de65809025ac86915e9cd1f52cf
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d91d1e681c999de65809025ac86915e9cd1f52cf



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[ Upstream commit 50719bf3 ]

These have been incorrect since the function was introduced.

A proper kerneldoc comment is added since this function, though
static, is part of an external interface.

Reported-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>