iwlwifi: create new subdirectory for FW interaction

There's a lot of mvm code that really should be more generic
and part of the iwlwifi module. Start by making a place to
keep such code - in the new "fw" subdirectory - and already
move the firmware related header files there.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/iwl-trans.h

@@ -74,9 +74,9 @@
 
 #include "iwl-debug.h"
 #include "iwl-config.h"
-#include "iwl-fw.h"
+#include "fw/img.h"
 #include "iwl-op-mode.h"
-#include "iwl-fw-api.h"
+#include "fw/api.h"
 
 /**
  * DOC: Transport layer - what is it ?