usb: gadget: uvc: configfs: Drop leaked references to config items

Some of the .allow_link() and .drop_link() operations implementations
call config_group_find_item() and then leak the reference to the
returned item. Fix this by dropping those references where needed.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Git-commit: 86f3daed
Git-repo: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>