media: dvb_net: avoid speculation from net slot

[ Upstream commit abc0226d ]

The risk of especulation is actually almost-non-existing here,
as there are very few users of TCP/IP using the DVB stack,
as, this is mainly used with DVB-S/S2 cards, and only by people
that receives TCP/IP from satellite connections, which limits
a lot the number of users of such feature(*).

(*) In thesis, DVB-C cards could also benefit from it, but I'm
yet to see a hardware that supports it.

Yet, fixing it is trivial.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I15da13081d5ac3f91cc6011ededdd0bb302f841a