The same MIB struct is used by drivers based on qca8k family switch. Move
it to common code to make it accessible also by other drivers.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>