NFSD: Update nfsd_cache_append() to use xdr_stream

stable inclusion
from stable-v6.6.3
commit 68eb0889fd03fb8e7518aeabb5d2064a01a3cfd3
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8LBQP

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=68eb0889fd03fb8e7518aeabb5d2064a01a3cfd3



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commit 49cecd8628a9855cd993792a0377559ea32d5e7c upstream.

When inserting a DRC-cached response into the reply buffer, ensure
that the reply buffer's xdr_stream is updated properly. Otherwise
the server will send a garbage response.

Cc: stable@vger.kernel.org # v6.3+
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>