usb: gadget: SourceSink: Remove out-of-date comment

As SourceSink function has been reworked for ConfigFS
composite gadget this comment is no longer valid.

Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_sourcesink.c

@@ -42,11 +42,6 @@
  * queues are relatively independent, will receive a range of packet sizes,
  * and can often be made to run out completely.  Those issues are important
  * when stress testing peripheral controller drivers.
- *
- *
- * This is currently packaged as a configuration driver, which can't be
- * combined with other functions to make composite devices.  However, it
- * can be combined with other independent configurations.
  */
 struct f_sourcesink {
 	struct usb_function	function;