net: Add comment explaining net_core's verdict values

It is then clear what logic to expect once such verdict has been given.

Change-Id: Id64ff00e65ffe2dad45673d1eca4eb76ae3ae1f6
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>

include/net/yaip/net_core.h

@@ -72,9 +72,10 @@ struct net_if;
 #include <string.h>
 
 enum net_verdict {
-	NET_OK,
-	NET_CONTINUE,
-	NET_DROP,
+	NET_OK,		/** Packet has been taken care of */
+	NET_CONTINUE,	/** Packet has not been touched,
+			    other part should decide about its fate */
+	NET_DROP,	/** Packet must be dropped */
 };
 
 /* Called by lower network stack when a network packet has been received */