usb: Support for removing device by host addr, improved auto filter syntax (Max Krasn...

usb: Support for removing device by host addr, improved auto filter syntax (Max Krasnyansky)

This patch adds support for removing USB devices by host address.
Which is usefull for things like libvirtd because there is no easy way to
find guest USB address of the host device.
In other words you can now do:
   usb_add host:3.5
   ...
   usb_del host:3.5
Before the patch 'usb_del' did not support 'host:' notation.

----
Syntax for specifying auto connect filters has been improved.
Old syntax was
    host:bus.dev
    host:pid:vid
New syntax is
    host:auto:bus.dev[:pid:vid]
In both the cases any attribute can be set to "*".

New syntax is more flexible and lets you do things like
    host:3.*:5533:* /* grab any device on bus 3 with vendor id 5533 */

It's now possible to remove auto filters. For example:
    usb_del host:auto:3.*:5533:*

Active filters are printed after all host devices in 'info usb' output.
Which now looks like this:

  Device 1.1, speed 480 Mb/s
    Hub: USB device 1d6b:0002, EHCI Host Controller
  Device 1.4, speed 480 Mb/s
    Class 00: USB device 1058:0704, External HDD
  Auto filters:
    Device 3.* ID *:*

Signed-off-by: Max Krasnyansky <maxk@kernel.org>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5205 c046a42c-6fe2-441c-8c8c-71466251a162