kernel: Add vlan feature

Add a vlan feature for systems that want vlan support.
Resolves openbmc/openbmc#1849.

Change-Id: I492bf1c75932a8a596b3440e914058d324300149
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/common/recipes-kernel/linux/linux-obmc/phosphor-vlan.cfg b/common/recipes-kernel/linux/linux-obmc/phosphor-vlan.cfg
new file mode 100644
index 0000000..1ea3eed
--- /dev/null
+++ b/common/recipes-kernel/linux/linux-obmc/phosphor-vlan.cfg
@@ -0,0 +1 @@
+CONFIG_VLAN_8021Q=y