UPSTREAM: usb: gadget: uvc: default the ctrl request interface offsets

For the userspace it is needed to distinguish between requests for the
control or streaming interface. The userspace would have to parse the
configfs to know which interface index it has to compare the ctrl
requests against. Since the interface numbers are not fixed, e.g. for
composite gadgets, the interface offset depends on the setup.

The kernel has this information when handing over the ctrl request to
the userspace. This patch removes the offset from the interface numbers
and expose the default interface defines in the uapi g_uvc.h.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20221011075348.1786897-1-m.grzeschik@pengutronix.de


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

(cherry picked from commit d182bf15)
Bug: 259171206
Change-Id: Ie5978ef268731e67ca72940ce6fbc7f980cb4419
Signed-off-by: Avichal Rakesh <arakesh@google.com>
(cherry picked from commit 044c3865)