iwlwifi: split firmware API from iwl-trans.h

In order to more clearly document which parts of this file
are firmware API and which are something else, split the
firmware API into a separate file to include here.

type=cleanup

Change-Id: I8706dc303f992c43baef1c81b38226d4123f2ec7
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
x-iwlwifi-stack-dev: 436786c8895cd24acbc91ec01a807217f1d681aa
3 files changed