Pull up following revision(s) (requested by riastradh in ticket #1065):

sys/dev/usb/usbdevices.config: revision 1.41 (patch)
sys/dev/usb/ugen.c: revision 1.152
sys/dev/usb/ugen.c: revision 1.153
sys/dev/usb/ugen.c: revision 1.154
sys/dev/usb/ugen.c: revision 1.155 (patch)
sys/dev/usb/ugen.c: revision 1.156
sys/dev/usb/ugen.c: revision 1.157

Remove UGEN_ASLP microoptimization.
cv_signal already has this microoptimization.
While here, make the lock cover the relevant things we're issuing
cv_signal about -- progress toward real MP-safety.

Hold the lock over access to the data structures it covers.
Still not MPSAFE, but progress.

Convert DIAGNOSTIC prints to KASSERTs.

Share unit numbering for ugen and ugenif.
This way putting ugenif in kernel config actually works to wire it to
the /dev/ugenN.MM device nodes in userland.

Not a fully fleshed out solution to the ugen problem -- there's no
way for a userland driver to kick out a kernel driver and take over,
but this will let us, e.g., use uhidev(4) for Yubikey OTP/U2F/FIDO2
but ugen(4), with pcscd(8), for Yubikey CCID.

Fix various MP-safety issues while here (still not MPSAFE, but more
progress).

Expose Yubikey CCID interface to userland via ugenif.

Fix sloppy mistakes in previous.
1. Give the offset of the rbnode, not some other random members to
  overwrite with garbage.
2. Don't try to unlock a mutex at NULL.
3. Make sure all paths out after ugenif_acquire go via
  ugenif_release.

Fix ugen detach after partial attach.

While here, register null pmf handler even for partially attached
devices so they don't needlessly interfere with suspend.

(martin)