kernel: tipc: Check the bearer type before calling tipc_udp_nl_bearer_add()

In the Linux kernel, the following vulnerability has been resolved: tipc: Check the bearer type before calling tipcudpnlbeareradd syzbot reported the following general protection fault 1: general protection fault, probably for non-canonical address 0xdffffc0000000010: 0000 1 PREEMPT SMP KASAN...