format:
cn_msg (CN_W1_IDX.CN_W1_VAL as id, len is equal to sizeof(struct
- w1_netlink_msg) plus number of masters multipled by 4)
+ w1_netlink_msg) plus number of masters multiplied by 4)
w1_netlink_msg (type: W1_LIST_MASTERS, len is equal to
number of masters multiplied by 4 (u32 size))
id0 ... idN