Remove last two references to legacy make

This last two LEGACY MAKE conditions slipped by.  The others were removed
in a previous commit.
sbin: Use socklen_t in a few places.
kernel/files: Comment out two lines for old USB wlan drivers.

In preparation for some usb4bsd wlan work.
kernel/usb4bsd: Port rum(4).

The driver behaves mostly stable but a few issues remain, such as
kldunloading cleanly.
kernel/usb4bsd: Omit 'if_' in building directories of network drivers.