treewide: drop MAC and MTU from interfaces (protocols)

treewide: drop MAC and MTU from interfaces (protocols)

Those are L2 options that are not part of interfaces (L3), should not be
set there and don't work. Setting MAC and MTU should be done at device
layer (config device) and is supported for basic types already.

Signed-off-by: Rafał Miłecki <[email protected]>
(cherry picked from commit 79947af064122438c803f3b7bc580ede093a26e4)