net: lapbether: fix issue of invalid opcode in lapbeth_open()

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

net: lapbether: fix issue of invalid opcode in lapbeth_open()

If lapb_register() failed when lapb device goes to up for the first time,

the NAPI is not disabled. As a result, the invalid opcode issue is

reported when the lapb device goes to up for the second time.

The stack info is as follows:

[ 1958.311422][T11356] kernel BUG at net/core/dev.c:6442!

[ 1958.312206][T11356] invalid opcode: 0000 [#1] PREEMPT SMP KASAN

[ 1958.315979][T11356] RIP: 0010:napi_enable+0x16a/0x1f0

[ 1958.332310][T11356] Call Trace:

[ 1958.332817][T11356] <TASK>

[ 1958.336135][T11356] lapbeth_open+0x18/0x90

[ 1958.337446][T11356] __dev_open+0x258/0x490

[ 1958.341672][T11356] __dev_change_flags+0x4d4/0x6a0

[ 1958.345325][T11356] dev_change_flags+0x93/0x160

[ 1958.346027][T11356] devinet_ioctl+0x1276/0x1bf0

[ 1958.346738][T11356] inet_ioctl+0x1c8/0x2d0

[ 1958.349638][T11356] sock_ioctl+0x5d1/0x750

[ 1958.356059][T11356] __x64_sys_ioctl+0x3ec/0x1790

[ 1958.365594][T11356] do_syscall_64+0x35/0x80

[ 1958.366239][T11356] entry_SYSCALL_64_after_hwframe+0x46/0xb0

[ 1958.377381][T11356] </TASK>