net: increase maximum frame size to accomediate VLAN packets

Ethernet packages with IEEE 802.1Q VLAN support may be up to 1522
bytes long. Increase the default size used to allocate packet
storage by 4 bytes. While at it, let git care about history and
rewrite the comment to represent the situation today only.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Reviewed-by: Tom Rini <trini@konsulko.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

include/net.h

@@ -465,20 +465,14 @@ struct icmp_hdr {
 #define IP_ICMP_HDR_SIZE	(IP_HDR_SIZE + ICMP_HDR_SIZE)
 
 /*
- * Maximum packet size; used to allocate packet storage.
- * TFTP packets can be 524 bytes + IP header + ethernet header.
- * Lets be conservative, and go for 38 * 16.  (Must also be
- * a multiple of 32 bytes).
- */
-/*
- * AS.HARNOIS : Better to set PKTSIZE to maximum size because
- * traffic type is not always controlled
- * maximum packet size =  1518
+ * Maximum packet size; used to allocate packet storage. Use
+ * the maxium Ethernet frame size as specified by the Ethernet
+ * standard including the 802.1Q tag (VLAN tagging).
+ * maximum packet size =  1522
  * maximum packet size and multiple of 32 bytes =  1536
  */
-#define PKTSIZE			1518
+#define PKTSIZE			1522
 #define PKTSIZE_ALIGN		1536
-/*#define PKTSIZE		608*/
 
 /*
  * Maximum receive ring size; that is, the number of packets