iwlwifi: mvm: combine LMAC scans into one

The last remaining difference between the regular scan and scheduled
scan flows for LMAC is the FW capabilities check for EBS scans.

Merge these checks into a new function and then combine the LMAC scan
functions into a single one.

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