UPSTREAM: usb: dwc3: ep0: sanity check test mode selector

UPSTREAM: usb: dwc3: ep0: sanity check test mode selector

In case host sends us an unsupported test mode, we
*must* stall this request. This will tell the host
that the selector is invalid and we won't put the
controller in unsupported test modes which could
have undetermined side-effects.

Change-Id: Iaf6a0ae78864efa342a514fdd5e6fc7f2e94e314
Signed-off-by: Fei Yang <fei.yang@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Wu Liang feng <wulf@rock-chips.com>
(cherry picked from commit ae411413760785a0a2ce6cb44d5afe95115aa24d)