Fixups to hold excelsior on chef

- Add android-core package to packages.mk. This is in build/ on
master/day, but not chef.
- Add coral-edgetpu-stable to multistrap list, to get python3-edgetpu

Change-Id: I20b66b9cec9617aaee73fcf6b8142a40f80726c5
diff --git a/multistrap.conf b/multistrap.conf
index aff9318..ecff2ef 100644
--- a/multistrap.conf
+++ b/multistrap.conf
@@ -3,10 +3,15 @@
 cleanup=true
 unpack=true
 bootstrap=main
-aptsources=main
+aptsources=main edgetpu
 noauth=true
 
 [main]
 packages=MAIN_PACKAGES
 source=https://packages.cloud.google.com/apt
 suite=mendel-chef
+
+[edgetpu]
+packages=
+source=https://packages.cloud.google.com/apt
+suite=coral-edgetpu-stable
diff --git a/packages.mk b/packages.mk
index a2651e2..100e61a 100644
--- a/packages.mk
+++ b/packages.mk
@@ -28,6 +28,7 @@
 $(eval $(call make-pbuilder-bsp-package-target,weston-mtk,graphics/wayland/weston, wayland-protocols-mtk mesa-mtk))
 $(eval $(call make-pbuilder-bsp-package-target,mesa-mtk,graphics/mesa, libdrm))
 $(eval $(call make-pbuilder-bsp-package-target,excelsior-mtkcam-prebuilts,packages/excelsior-mtkcam-prebuilts))
+$(eval $(call make-pbuilder-bsp-package-target,android-core,android-core))
 $(eval $(call make-pbuilder-bsp-package-target,excelsior-mtkcam,packages/excelsior-mtkcam,excelsior-mtkcam-prebuilts android-core excelsior-nvram))
 $(eval $(call make-pbuilder-bsp-package-target,glmark2,graphics/glmark2,weston-mtk))
 $(eval $(call make-pbuilder-bsp-package-target,excelsior-vpu-prebuilts,multimedia/vpu))