iwlwifi: mvm: BT Coex - new API

Start the new BT Coex implementation.
Don't react to notifications for now - only the initial
configuration is implemented. The rest will happen in next
patches.
Since coex.c now uses the new the new structures in all
functions, we need to adapt the code to compile, even if it
doesn't run yet.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>