NFS: remove unneeded check in decode_devicenotify_args()

stable inclusion
from stable-4.19.238
commit 97cc035bdfe754dbfbc2c9b04bc46bc71ef5bc93
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5A6BA
CVE: NA

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[ Upstream commit cb8fac6d ]

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Overflow check in not needed anymore after we switch to kmalloc_array().

Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Fixes: a4f743a6 ("NFSv4.1: Convert open-coded array allocation calls to kmalloc_array()")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>