iwlwifi: mvm: rs: fix handling of column switch error

If we can't switch to a column because no rates are supported
in that column this led to a state where the search cycle
got stuck and never ended. This in turn also led to aggregation
not being turned on. Fix this by marking a column as
visited if we can't switch to it.

Reported-and-tested-by: Karl Beldan <karl.beldan@gmail.com>
Signed-off-by: Eyal Shapira <eyal@wizery.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>