meta-google: gbmc-ncsi-config: Add relay support for the bridge

We may have multiple BMCs running on the internal gbmcbr network via USB
links to attached trays. These BMCs do not have a direct connection to
the network, and require the NCSI BMC to relay all of their traffic
(including DHCP) out opf the machine. This patch enables dhcrelay to run
on the NCSI interface and proxy all DHCP traffic from the bridge out of
the machine.

Change-Id: I60f97ae2d64289c7b706b3d0a6c8fb79a931e485
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/meta-google/recipes-kernel/linux/files/gbmc.cfg b/meta-google/recipes-kernel/linux/files/gbmc.cfg
index 89e1ef9..056ee91 100644
--- a/meta-google/recipes-kernel/linux/files/gbmc.cfg
+++ b/meta-google/recipes-kernel/linux/files/gbmc.cfg
@@ -36,6 +36,7 @@
 CONFIG_BRIDGE_NETFILTER=y
 CONFIG_NF_TABLES_BRIDGE=y
 CONFIG_BRIDGE_NF_EBTABLES=y
+CONFIG_VETH=y
 
 # Remove features we won't use
 CONFIG_WLAN=n