iwlwifi: add a pointer to the trans_cfg directly in trans

Add a pointer to the iwl_trans structure and point it to the trans
part of the cfg.  This is the first step in disassociating the trans
configuration from the rest of the configuration.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

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

@@ -127,7 +127,7 @@
 static inline unsigned int FH_MEM_CBBC_QUEUE(struct iwl_trans *trans,
 					     unsigned int chnl)
 {
-	if (trans->cfg->trans.use_tfh) {
+	if (trans->trans_cfg->use_tfh) {
 		WARN_ON_ONCE(chnl >= 64);
 		return TFH_TFDQ_CBB_TABLE + 8 * chnl;
 	}