net/ipv6/addrconf: IPv6 tethering enhancement

Added new procfs flag to toggle the automatic addition of prefix
routes on a per device basis. The new flag is accept_ra_prefix_route.
Defaults to 1 as to not break existing behavior.

Change-Id: If25493890c7531c27f5b2c4855afebbbbf5d072a
CRs-Fixed: 504095
Signed-off-by: Harout Hedeshian <harouth@codeaurora.org>
diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index d42c279..acb60be 100644
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -524,6 +524,7 @@
 	{ CTL_INT,	NET_IPV6_ACCEPT_RA_RT_INFO_MAX_PLEN,	"accept_ra_rt_info_max_plen" },
 	{ CTL_INT,	NET_IPV6_PROXY_NDP,			"proxy_ndp" },
 	{ CTL_INT,	NET_IPV6_ACCEPT_SOURCE_ROUTE,		"accept_source_route" },
+	{ CTL_INT,	NET_IPV6_ACCEPT_RA_PREFIX_ROUTE,	"accept_ra_prefix_route" },
 	{}
 };