iwlwifi: Make use of the helper macro LIST_HEAD()

Replace "struct list_head head = LIST_HEAD_INIT(head)" with
"LIST_HEAD(head)" to simplify the code.
Signed-off-by: Cai Huoqing <cai.huoqing@linux.dev>
Link: https://lore.kernel.org/r/20220209032322.37472-1-cai.huoqing@linux.devSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/fw/dbg.c

@@ -2604,7 +2604,7 @@ static void iwl_fw_error_dump_data_free(struct iwl_fwrt_dump_data *dump_data)
 static void iwl_fw_error_ini_dump(struct iwl_fw_runtime *fwrt,
 				  struct iwl_fwrt_dump_data *dump_data)
 {
-	struct list_head dump_list = LIST_HEAD_INIT(dump_list);
+	LIST_HEAD(dump_list);
 	struct scatterlist *sg_dump_data;
 	u32 file_len = iwl_dump_ini_file_gen(fwrt, dump_data, &dump_list);