usb: gadget: f_hid: Fix zero length packet transfer

Set the hid req->zero flag of ep0/in_ep to true by default,
then the UDC drivers can transfer a zero length packet at
the end if the hid transfer with size divisible to EPs max
packet size according to the USB 2.0 spec.

Signed-off-by: William Wu <william.wu@rock-chips.com>
Link: https://lore.kernel.org/r/1756204087-26111-1-git-send-email-william.wu@rock-chips.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>