CVE-2022-49862: tipc: fix the msg->req tlv len check in tipc_nl_compat_name_table_dump_header

In the Linux kernel, the following vulnerability has been resolved:

tipc: fix the msg->req tlv len check in tipcnlcompatnametabledumpheader

This is a follow-up for commit 974cb0e3e7c9 ("tipc: fix uninit-value in tipcnlcompatnametabledump") where it should have type casted sizeof(..) to int to work when TLVGETDATALEN() returns a negative value.

syzbot reported a call trace because of it:

BUG: KMSAN: uninit-value in ... tipcnlcompatnametabledump+0x841/0xea0 net/tipc/netlinkcompat.c:934 tipcnlcompatdumpit+0xab2/0x1320 net/tipc/netlinkcompat.c:238 tipcnlcompatdumpit+0x991/0xb50 net/tipc/netlinkcompat.c:321 tipcnlcompatrecv+0xb6e/0x1640 net/tipc/netlinkcompat.c:1324 genlfamilyrcvmsgdoit net/netlink/genetlink.c:731 [inline] genlfamilyrcvmsg net/netlink/genetlink.c:775 [inline] genlrcvmsg+0x103f/0x1260 net/netlink/genetlink.c:792 netlinkrcvskb+0x3a5/0x6c0 net/netlink/afnetlink.c:2501 genlrcv+0x3c/0x50 net/netlink/genetlink.c:803 netlinkunicastkernel net/netlink/afnetlink.c:1319 [inline] netlinkunicast+0xf3b/0x1270 net/netlink/afnetlink.c:1345 netlinksendmsg+0x1288/0x1440 net/netlink/afnetlink.c:1921 socksendmsgnosec net/socket.c:714 [inline] socksendmsg net/socket.c:734 [inline]