usb: renesas_usbhs: gadget: fix re-enabling pipe without re-connecting

This patch fixes an issue that the renesas_usbhs driver in gadget mode
cannot work correctly even if I disabled DMAC of the driver when I used
the g_zero driver and the testusb tool.

When a usb cable is re-connected, the renesas_usbhs driver calls the
usbhsp_flags_init() (via usbhs_hotplug() --> usbhs_mod_call(start) -->
usbhsg_try_start() --> usbhs_pipe_init()). However, the driver doesn't
call the usbhsp_flags_init() when usbhsg_ep_disable() is called.
So, if a gadget driver calls usb_ep_enable() and usb_ep_disable() again
and again, the renesas_usbhs driver will output the following log:

  renesas_usbhs renesas_usbhs: can't get pipe (BULK)
  renesas_usbhs renesas_usbhs: wrong recip request

Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c b/drivers/usb/renesas_usbhs/mod_gadget.c
index 458f376..04e6505 100644
--- a/drivers/usb/renesas_usbhs/mod_gadget.c
+++ b/drivers/usb/renesas_usbhs/mod_gadget.c
@@ -600,8 +600,10 @@
 static int usbhsg_ep_disable(struct usb_ep *ep)
 {
 	struct usbhsg_uep *uep = usbhsg_ep_to_uep(ep);
+	struct usbhs_pipe *pipe = usbhsg_uep_to_pipe(uep);
 
 	usbhsg_pipe_disable(uep);
+	usbhs_pipe_free(pipe);
 
 	uep->pipe->mod_private	= NULL;
 	uep->pipe		= NULL;