bit_field crate: Clean-up of CL:3345830

Resolve the comment - https://android-review.git.corp.google.com/c/platform/external/rust/android-crates-io/+/3345830/comment/30cad597_53f7d1d3/.

Test: m libbit_field_nostd
Bug: 237386071
Change-Id: I7a12fa6ef7dae111f13521214a51c8d489b3764d
diff --git a/crates/bit_field/cargo_embargo.json b/crates/bit_field/cargo_embargo.json
index 905a70b..e4548ae 100644
--- a/crates/bit_field/cargo_embargo.json
+++ b/crates/bit_field/cargo_embargo.json
@@ -1,18 +1,14 @@
 {
   "run_cargo": false,
   "generate_rulesmk": true,
-  "variants": [
-    {
-      "module_name_overrides": {
-        "libbit_field": "libbit_field_nostd"
-      },
-      "package": {
-        "bit_field": {
-          "force_rlib": true,
-          "host_supported": false,
-          "no_std": true
-        }
-      }
+  "module_name_overrides": {
+    "libbit_field": "libbit_field_nostd"
+  },
+  "package": {
+    "bit_field": {
+      "force_rlib": true,
+      "host_supported": false,
+      "no_std": true
     }
-  ]
+  }
 }