ramips: Fix multicast ICMPv6 for the rt3050 ethernet switch.

The FCT2 esw register should be set to 0x2500C to have "unknown IPv6
multicast" packets broadcasted to every port, instead of dropped.
The previous value only let those packets go through ports 1 and 3.

"Unknown IPv6 multicast" packets include packets needed by ICMPv6 echo
requests addressed to well-known addresses, such as ff02::1 (MAC address
is 33:33:00:00:00:01 in this case).

Please note that by default ICMPv6 echo requests to ff02::1 are not replied
to by the router because of ip6tables considering those packets to be invalid.
But this is another bug/patch. ;)

Signed-off-by: Vittorio Gambaletta <[email protected]>

SVN-Revision: 49287

target/linux/ramips/patches-4.4/0515-net-mediatek-fix-multicast-icmpv6-for-the-rt3050-eth.patch

@@ -0,0 +1,26 @@
+From: Vittorio Gambaletta <[email protected]>
+Date: Mon, 02 May 2016 04:55:48 +0200
+Subject: [PATCH] net: mediatek: Fix multicast ICMPv6 for the rt3050 ethernet switch.
+
+The FCT2 esw register should be set to 0x2500C to have "unknown IPv6
+multicast" packets broadcasted to every port, instead of dropped.
+The previous value only let those packets go through ports 1 and 3.
+
+"Unknown IPv6 multicast" packets include packets needed by ICMPv6 echo
+requests addressed to well-known addresses, such as ff02::1 (MAC address
+is 33:33:00:00:00:01 in this case).
+
+Signed-off-by: Vittorio Gambaletta <[email protected]>
+---
+
+--- a/drivers/net/ethernet/mediatek/esw_rt3050.c
++++ b/drivers/net/ethernet/mediatek/esw_rt3050.c
+@@ -450,7 +450,7 @@ static void esw_hw_init(struct rt305x_es
+ 		      (RT305X_ESW_PORTS_NOCPU << RT305X_ESW_POC2_UNTAG_EN_S)),
+ 		RT305X_ESW_REG_POC2);
+ 
+-	esw_w32(esw, 0x00d6500c, RT305X_ESW_REG_FCT2);
++	esw_w32(esw, 0x0002500c, RT305X_ESW_REG_FCT2);
+ 
+ 	/* 300s aging timer, max packet len 1536, broadcast storm prevention
+ 	 * disabled, disable collision abort, mac xor48 hash, 10 packet back