[bazel] Build verilator with bazel

1. Add a rule to allow bazel to dispatch the verilator build to FuseSoC.
2. Create an `all_files` target in the //hw/... hierarchy to give to
   the fusesoc rule.

Signed-off-by: Chris Frantz <cfrantz@google.com>

foo
diff --git a/hw/ip/sysrst_ctrl/BUILD b/hw/ip/sysrst_ctrl/BUILD
new file mode 100644
index 0000000..9b178b7
--- /dev/null
+++ b/hw/ip/sysrst_ctrl/BUILD
@@ -0,0 +1,12 @@
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "all_files",
+    srcs = glob(["**"]) + [
+        "//hw/ip/sysrst_ctrl/data:all_files",
+    ],
+)