[PATCH v2] usb: gadget: make usb_ep_enable return -EBUSY if ep has already enabled

From: "Du, Changbin" When usb_ep_enable on a enabled ep, the configuration of the ep probably has changed. In this scenario, the ep configuration in hw should be reprogrammed by udc driver. Hence, it is better to return an error to inform the caller. Signed-off-by: Du, Changbin --- change from

[PATCH v2] usb: gadget: make usb_ep_enable return -EBUSY if ep has already enabled

From: "Du, Changbin" When usb_ep_enable on a enabled ep, the configuration of the ep probably has changed. In this scenario, the ep configuration in hw should be reprogrammed by udc driver. Hence, it is better to return an error to inform the caller. Signed-off-by: Du,