iwlwifi: mvm: begin basic BT-Coex implementation

Send the PRIO table before the calibrations. This table
tells the fw what priority to give to what (WiFi / BT)
according to events.

Send a hardcoded BT_COEX command to the fw to enable basic
BT coexistence.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>