usb: split endpoint init and reset

Create a new usb_ep_reset() function to reset endpoint state, without
re-initialiting the queues, so we don't unlink in-flight packets just
because usb-host has to re-parse the descriptor tables.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/hw/usb/core.c b/hw/usb/core.c
index 0e02da7..fe15be0 100644
--- a/hw/usb/core.c
+++ b/hw/usb/core.c
@@ -550,7 +550,7 @@
     qemu_iovec_destroy(&p->iov);
 }
 
-void usb_ep_init(USBDevice *dev)
+void usb_ep_reset(USBDevice *dev)
 {
     int ep;
 
@@ -559,7 +559,6 @@
     dev->ep_ctl.ifnum = 0;
     dev->ep_ctl.dev = dev;
     dev->ep_ctl.pipeline = false;
-    QTAILQ_INIT(&dev->ep_ctl.queue);
     for (ep = 0; ep < USB_MAX_ENDPOINTS; ep++) {
         dev->ep_in[ep].nr = ep + 1;
         dev->ep_out[ep].nr = ep + 1;
@@ -573,6 +572,16 @@
         dev->ep_out[ep].dev = dev;
         dev->ep_in[ep].pipeline = false;
         dev->ep_out[ep].pipeline = false;
+    }
+}
+
+void usb_ep_init(USBDevice *dev)
+{
+    int ep;
+
+    usb_ep_reset(dev);
+    QTAILQ_INIT(&dev->ep_ctl.queue);
+    for (ep = 0; ep < USB_MAX_ENDPOINTS; ep++) {
         QTAILQ_INIT(&dev->ep_in[ep].queue);
         QTAILQ_INIT(&dev->ep_out[ep].queue);
     }