cam(4): Fix a few typos in source code comments

- s/trafer/transfer/
- s/failes/fails/

Obtained from:	NetBSD
MFC after:	3 days

sys/cam/cam_queue.c

@@ -76,7 +76,7 @@ camq_init(struct camq *camq, int size)
 
 /*
  * Free a camq structure.  This should only be called if a controller
- * driver failes somehow during its attach routine or is unloaded and has
+ * driver fails somehow during its attach routine or is unloaded and has
  * obtained a camq structure.  The XPT should ensure that the queue
  * is empty before calling this routine.
  */

sys/cam/scsi/scsi_ch.h

@@ -440,7 +440,7 @@ struct page_element_address_assignment {
 	/* First data transfer element address */
 	u_int8_t	fdtea[2];
 
-	/* Number of data trafer elements */
+	/* Number of data transfer elements */
 	u_int8_t	ndte[2];
 
 	u_int8_t	reserved[2];