usb: dwc2: gadget: Remove unnecessary line

Removed "ctrl |= DXEPCTL_USBACTEP" from
dwc2_hsotg_start_req() function because this
step is done in dwc2_hsotg_ep_enable().

Tested-by: John Keeping <john@metanate.com>
Signed-off-by: Vardan Mikayelyan <mvardan@synopsys.com>
Signed-off-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>