net: drop special comment style

As we discussed in the room at netdevconf earlier this week,
drop the requirement for special comment style for netdev.

For checkpatch, the general check accepts both right now, so
simply drop the special request there as well.

Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>