tools: usbip: list.h: fix kernel-doc for list_del()

tools: usbip: list.h: fix kernel-doc for list_del()

In list.h, the kernel-doc for list_del() should be immediately
preceding the implementation and not separated from it by
another function implementation.

Eliminates this kernel-doc error:
list.h:1: warning: 'list_del' not found

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Valentina Manea <valentina.manea.m@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/r/20210325174724.14447-1-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>