add seccomp to DISTRO_FEATURES

Commit aff0243 added seccomp to the systemd PACKAGECONFIG. The
libseccomp recipe requires seccomp be a DISTRO_FEATURE.

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: Iee1d5e9b2efe8284454c0b5125d9de7b43c1bdb0
diff --git a/meta-phosphor/conf/distro/include/phosphor-base.inc b/meta-phosphor/conf/distro/include/phosphor-base.inc
index 8c5e4fc..731f9f1 100644
--- a/meta-phosphor/conf/distro/include/phosphor-base.inc
+++ b/meta-phosphor/conf/distro/include/phosphor-base.inc
@@ -102,6 +102,7 @@
         security \
         slp \
         systemd \
+        seccomp \
         "
 
 DISTRO_FEATURES += " \