usb: gadget: f_uvc: Fix SuperSpeed companion descriptor's wBytesPerInterval

The streaming_maxburst module parameter is 0 offset (0..15)
so we must add 1 while using it for wBytesPerInterval
calculation for the SuperSpeed companion descriptor.

Without this host uvcvideo driver will always see the wrong
wBytesPerInterval for SuperSpeed uvc gadget and may not find
a suitable video interface endpoint.
e.g. for streaming_maxburst = 0 case it will always
fail as wBytePerInterval was evaluating to 0.

Cc: stable@vger.kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>