usb: raw-gadget: support stalling/halting/wedging endpoints

usb: raw-gadget: support stalling/halting/wedging endpoints

Raw Gadget is currently unable to stall/halt/wedge gadget endpoints,
which is required for proper emulation of certain USB classes.

This patch adds a few more ioctls:

- USB_RAW_IOCTL_EP0_STALL allows to stall control endpoint #0 when
  there's a pending setup request for it.
- USB_RAW_IOCTL_SET/CLEAR_HALT/WEDGE allow to set/clear halt/wedge status
  on non-control non-isochronous endpoints.

Fixes: f2c2e717642c ("usb: gadget: add raw-gadget interface")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>