usb: gadget: net2280: don't set ep_cfg.direction bit

USB3380 ep_cfg.direction bit is reserved in enhanced mode. Don't set
it.

Tested-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>