usb: dwc2: Fixed a few typos in comments

Fixed 3 typos in comments

Signed-off-by: Mickael Maison <mickael.maison@gmail.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 7a70a13..0d2ee29 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -381,7 +381,7 @@
  * @power_optimized     Are power optimizations enabled?
  * @num_dev_ep          Number of device endpoints available
  * @num_dev_perio_in_ep Number of device periodic IN endpoints
- *                      avaialable
+ *                      available
  * @dev_token_q_depth   Device Mode IN Token Sequence Learning Queue
  *                      Depth
  *                       0 to 30