usb: cdns3: ep0: Move 'zlp' description to appropriate function header

usb: cdns3: ep0: Move 'zlp' description to appropriate function header

'zlp' was documented, but in the wrong place.

Fixes the following W=1 kernel build warning(s):

 drivers/usb/cdns3/ep0.c:36: warning: Function parameter or member 'zlp' not described in 'cdns3_ep0_run_transfer'
 drivers/usb/cdns3/ep0.c:705: warning: Excess function parameter 'zlp' description in 'cdns3_gadget_ep0_queue'

Cc: Pawel Laszczak <pawell@cadence.com>
Cc: Pawel Jez <pjez@cadence.com>
Cc: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20200702144625.2533530-23-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>