usb: renesas_usbhs: gadget: Fix usb_ep_set_{halt,wedge}() behavior

usb: renesas_usbhs: gadget: Fix usb_ep_set_{halt,wedge}() behavior

According to usb_ep_set_halt()'s description,
__usbhsg_ep_set_halt_wedge() should return -EAGAIN if the IN endpoint
has any queue or data. Otherwise, this driver is possible to cause
just STALL without sending a short packet data on g_mass_storage driver,
and then a few resetting a device happens on a host side during
a usb enumaration.

Fixes: 3cc1bc271551 ("usb: renesas_usbhs: Add Renesas USBHS Gadget")
Cc: <stable@vger.kernel.org> # v3.0+
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/1569924633-322-3-git-send-email-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>