bonding: trivial: style and comment fixes

First adjust a couple of locking comments that were left inaccurate,
then adjust comments to use the netdev styling and remove extra new
lines where necessary and add a couple of new lines between declarations
and code. These are all trivial styling changes, no functional change.
Also removed a couple of outdated or obvious comments.
This patch is by no means a complete fix of all netdev style violations
but it gets the bonding closer.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>