Add some missing sha256s

These help bazel cache better. With a future version, they will be
required.

Change-Id: Ibdee3416f15df342654262fb42d499277c430018
diff --git a/WORKSPACE b/WORKSPACE
index 168e690..dced1f0 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -681,6 +681,7 @@
 http_archive(
     name = "halide_k8",
     build_file = "@//debian:halide.BUILD",
+    sha256 = "c67185d50a99adba86f6b2cc43c7e2cf11bcdfba9052d05e764a89b456a50446",
     strip_prefix = "halide/",
     url = "http://www.frc971.org/Build-Dependencies/halide-linux-64-gcc53-800-65c26cba6a3eca2d08a0bccf113ca28746012cc3.tgz",
 )
@@ -691,6 +692,7 @@
 http_archive(
     name = "halide_armhf",
     build_file = "@//debian:halide.BUILD",
+    sha256 = "10564c559c9e04a173823413916d05fadd6e697d91bab21ddc5041190fa8f0f0",
     strip_prefix = "halide/",
     url = "http://www.frc971.org/Build-Dependencies/halide-arm32-linux-32-trunk-65c26cba6a3eca2d08a0bccf113ca28746012cc3.tgz",
 )