media: drop unnecessary networking includes

dvb_net.h includes a bunch of core networking headers which increases
the number of objects rebuilt when we touch them. They are unnecessary
for the header itself and only one driver has an indirect dependency.

tveeprom.h includes if_packet to gain access to ETH_ALEN. This
is a bit of an overkill because if_packet.h pulls in skbuff.h.
The definition of ETH_ALEN is in the uAPI header, which is
very rarely touched, so switch to including that.

This results in roughly 250 fewer objects built when skbuff.h
is touched (6028 -> 5788).

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>