FROMGIT: usb: gadget: uvc: fix sg handling during video encode

In uvc_video_encode_isoc_sg, the uvc_request's sg list is
incorrectly being populated leading to corrupt video being
received by the remote end. When building the sg list the
usage of buf->sg's 'dma_length' field is not correct and
instead its 'length' field should be used.

Fixes: e81e7f9a ("usb: gadget: uvc: add scatter gather support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Jeff Vanhoof <qjv001@motorola.com>
Signed-off-by: Dan Vacura <w36195@motorola.com>
Link: https://lore.kernel.org/r/20221018215044.765044-5-w36195@motorola.com


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

Bug: 249635012
(cherry picked from commit b57b08e6
https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git

 usb-linus)
Change-Id: Ie8839a84abf3be1314116929c232165c20765df2
Signed-off-by: Dan Vacura <w36195@motorola.com>