[prim_mubi_pkg] Add a generic multibit type and associated functions

Signed-off-by: Michael Schaffner <msf@google.com>
diff --git a/hw/ip/prim/prim_mubi.core b/hw/ip/prim/prim_mubi.core
new file mode 100644
index 0000000..f400a3e
--- /dev/null
+++ b/hw/ip/prim/prim_mubi.core
@@ -0,0 +1,17 @@
+CAPI=2:
+# Copyright lowRISC contributors.
+# Licensed under the Apache License, Version 2.0, see LICENSE for details.
+# SPDX-License-Identifier: Apache-2.0
+
+name: "lowrisc:prim:mubi:0.1"
+description: "Multibit types and functions"
+filesets:
+  files_rtl:
+    files:
+      - rtl/prim_mubi_pkg.sv
+    file_type: systemVerilogSource
+
+targets:
+  default:
+    filesets:
+      - files_rtl