iwlwifi: mvm: move all UMAC scan flags setting into the relevant function

Clean the code a little by moving all the flags into the right
function.  Additionally, rename the function, since "common" is now
irrelevant.

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