usb: core: Remove unused usb_unlink_anchored_urbs

usb_unlink_anchored_urbs() has been unused since it's last use was
removed in 2009 by
commit 9b9c5aae ("ar9170: xmit code revamp")

Remove it.

Signed-off-by: "Dr. David Alan Gilbert" <linux@treblig.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20250608235617.200731-1-linux@treblig.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>