6lowpan: Fix some typos in nhc_udp.c

s/Orignal/Original/
s/infered/inferred/

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: Wang Hai <[e-mail]>
Acked-by: Randy Dunlap <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/6lowpan/nhc_udp.c

···
  *	Authors:
  *	Alexander Aring	<[e-mail]>
  *
- *	Orignal written by:
+ *	Original written by:
  *	Alexander Smirnov <[e-mail]>
  *	Jon Smirl <[e-mail]>
  */
···
 	if (fail)
 		return -EINVAL;
 
-	/* UDP length needs to be infered from the lower layers
+	/* UDP length needs to be inferred from the lower layers
 	 * here, we obtain the hint from the remaining size of the
 	 * frame
 	 */