usb: gadget: amd5536udc: fix spelling mistake "reserverd" -> "reserved"

The variable is named reserved, the comment should say so.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/udc/amd5536udc.h

@@ -440,7 +440,7 @@ struct udc_ep_regs {
 	/* endpoint data descriptor pointer */
 	u32 desptr;
 
-	/* reserverd */
+	/* reserved */
 	u32 reserved;
 
 	/* write/read confirmation */