bus: mhi: fix typo in comments for struct mhi_channel_config

The word 'rung' is a typo in below comment, fix it.
* @event_ring: The event rung index that services this channel
Signed-off-by: Jarvis Jiang <jarvis.w.jiang@gmail.com>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20210408100220.3853-1-jarvis.w.jiang@gmail.comSigned-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

include/linux/mhi.h

@@ -205,7 +205,7 @@ enum mhi_db_brst_mode {
  * @num: The number assigned to this channel
  * @num_elements: The number of elements that can be queued to this channel
  * @local_elements: The local ring length of the channel
- * @event_ring: The event rung index that services this channel
+ * @event_ring: The event ring index that services this channel
  * @dir: Direction that data may flow on this channel
  * @type: Channel type
  * @ee_mask: Execution Environment mask for this channel