Unfortunately, usb_set_configuration() is widely mis-used as a
lightweight device reset.  That's trouble because setting a
configuration must sometimes involve things that don't relate
at all to a light reset, and can't be done in contexts like
driver probe() calls.

This patch updates most usb_set_configuration() users to use a call
that provides more appropriate functionality:

  - Adds a new usb_reset_configuration() call, which never needs
    to change very much usbcore state.

  - Uses it to replace most usb_set_configuration() calls, in
    many serial drivers, hisax, dvb, irda, and so on.

  - Modifies usb_reset_device() so it issues the control request
    directly.  It's both more of a reset (hides a USB reset) and
    less of one (altsettings are unchanged).

  - Makes usbfs return the error code instead of discarding it.

Once this goes in, then usb_set_configuration() can be made to
work properly (including from sysfs).