libusb: fix netlink multicast subsystem name

[aokblast]

Use

genl

Then the output shows:

Name: nlsysevent
        ID: 0x13, Version: 00, header size: 2, max attributes: 4
        multicast groups:
          - ID: 0x34, Name: ACPI
          - ID: 0x35, Name: AEON
          - ID: 0x36, Name: CAM
          - ID: 0x37, Name: CARP
          - ID: 0x38, Name: coretemp
          - ID: 0x39, Name: DEVFS
          - ID: 0x3a, Name: device
          - ID: 0x3b, Name: ETHERNET
          - ID: 0x3c, Name: GEOM
          - ID: 0x3d, Name: HYPERV_NIC_VF
          - ID: 0x3e, Name: IFNET
          - ID: 0x3f, Name: INFINIBAND
          - ID: 0x40, Name: KERNEL
          - ID: 0x41, Name: nvme
          - ID: 0x42, Name: PMU
          - ID: 0x43, Name: RCTL
          - ID: 0x44, Name: USB
          - ID: 0x45, Name: VFS
          - ID: 0x46, Name: VT
          - ID: 0x47, Name: ZFS

[hrs]

Looks good to me.

[aokblast]

Please use this patch for merging if there is no problem. Thanks!

https://github.com/aokblast/freebsd-src/commit/811af380964a3280bb6dbe69c909112938598ad2

[aokblast]

Can this patch be MFCed to 14? If not, it makes all hot-plug detection unable to work.