build-seed: add gbs platform

A new platform is coming to CI so ensure we seed it in our build
machines

Change-Id: I33e35aa604641cd08f39869fbd38e2d6bbaa31c9
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/jenkins/build-seed b/jenkins/build-seed
index 89b348e..131285d 100755
--- a/jenkins/build-seed
+++ b/jenkins/build-seed
@@ -24,6 +24,7 @@
 export build_dir="${WORKSPACE}/build"
 
 SEED_MACHINES=(
+    gbs
     gsj
     p10bmc
     palmetto