greybus: es2: fix typo in a comment

The double `for' in the comment in line 81 is repeated. Remove one
of them from the comment.
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Link: https://lore.kernel.org/r/20211212031657.41169-1-wangborong@cdjrlc.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/greybus/es2.c

@@ -78,7 +78,7 @@ struct es2_cport_in {
  * @hd: pointer to our gb_host_device structure
  *
  * @cport_in: endpoint, urbs and buffer for cport in messages
- * @cport_out_endpoint: endpoint for for cport out messages
+ * @cport_out_endpoint: endpoint for cport out messages
  * @cport_out_urb: array of urbs for the CPort out messages
  * @cport_out_urb_busy: array of flags to see if the @cport_out_urb is busy or
  *			not.