[ion] DFU driver: fix action following enumeration interruption

An end-point reset was added to fix a enumeration problem. But, it
triggered another issue: the calculator freezes because of a SEDET (end
of session) detection. Plus, the initial bug doesn't seem to exist now.

ion/src/device/shared/usb/stack/device.cpp

@@ -73,8 +73,6 @@ void Device::poll() {
     /* After a USB reset, the host talks to the device by sending messages to
      * address 0; */
     setAddress(0);
-    // Flush the FIFOs
-    m_ep0.reset();
     m_ep0.setup();
     /* In setup(), we should set the MPSIZ field in OTG_DIEPCTL0 to the maximum
      * packet size depending on the enumeration speed (found in OTG_DSTS). We

ion/src/device/shared/usb/stack/endpoint0.cpp

@@ -186,8 +186,7 @@ void Endpoint0::flushTxFifo() {
   OTG.DIEPCTL0()->setSNAK(true);
 
   // Wait for core to respond
-  // TODO: understand why !OTG.GOTGINT()->getSEDET() is required since verion 16
-  while (!OTG.DIEPINT(0)->getINEPNE() && !OTG.GOTGINT()->getSEDET()) {
+  while (!OTG.DIEPINT(0)->getINEPNE()) {
   }
 
   // Get the Tx FIFO number