usb: dwc3: fix typo in comment of dwc3_ep

Change intervall into interval.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/core.h

@@ -398,7 +398,7 @@ struct dwc3_event_buffer {
  * @number: endpoint number (1 - 15)
  * @type: set to bmAttributes & USB_ENDPOINT_XFERTYPE_MASK
  * @resource_index: Resource transfer index
- * @interval: the intervall on which the ISOC transfer is started
+ * @interval: the interval on which the ISOC transfer is started
  * @name: a human readable name e.g. ep1out-bulk
  * @direction: true for TX, false for RX
  * @stream_capable: true when streams are enabled