9p: Fix read/write debug statements to report server reply

[ Upstream commit be3193e5 ]

Previous conversion to iov missed these debug statements which would now
always print the requested size instead of the actual server reply.

Write also added a loop in a much older commit but we didn't report
these, while reads do report each iteration -- it's more coherent to
keep reporting all requests to server so move that at the same time.

Fixes: 7f024647

 ("9p: convert to advancing variant of iov_iter_get_pages_alloc()")
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Message-ID: <20240109-9p-rw-trace-v1-1-327178114257@codewreck.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>