iwlwifi: mvm: simplify the channel switch flow for newer firmware

Any firmware that supports the new channel switch flow is
able to close / re-open the queues when needed. It takes
into account the channel switch mode etc...
Don't open / close the queues or enable / disable beacon
abort before and after the channel switch in case the
firmware is able to do this by itself.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>