usb: gadget: uvc: allow changing interface name via configfs

Add a configfs entry, "function_name", to change the iInterface field
for VideoControl. This name is used on host devices for user selection,
useful when multiple cameras are present. The default will remain "UVC
Camera".

Signed-off-by: Dan Vacura <w36195@motorola.com>
Link: https://lore.kernel.org/r/20220401160447.5919-1-w36195@motorola.com


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