Merge branch 'net-constify-device_type'

Ricardo B. Marliere says:

====================
net: constify struct device_type usage

This is a simple and straight forward cleanup series that makes all device
types in the net subsystem constants. This has been possible since 2011 [1]
but not all occurrences were cleaned. I have been sweeping the tree to fix
them all.

I was not sure if I should send these squashed, but there are quite a few
changes so I decided to send them separately. Please let me know if that is
not desirable.

[1] https://lore.kernel.org/all/1305850262-9575-5-git-send-email-gregkh@suse.de/

====================

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>