iwlwifi: add fall through comment

The fall-through to the MVM case is intended as we have to do
*something* to continue, and can't easily clean up. So we'll
just fail in mvm later, if this does happen.

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

drivers/net/wireless/intel/iwlwifi/iwl-drv.c

@@ -1471,6 +1471,7 @@ static void iwl_req_fw_callback(const struct firmware *ucode_raw, void *context)
 		break;
 	default:
 		WARN(1, "Invalid fw type %d\n", fw->type);
+		/* fall through */
 	case IWL_FW_MVM:
 		op = &iwlwifi_opmode_table[MVM_OP_MODE];
 		break;