Generate rules.mk for coset via cargo_embargo

Update cargo_embargo.json to also generate Trusty rules.mk for use
in the Trusty kernel.

Test: cargo_embargo generate cargo_embargo.json
Change-Id: I35464bc235f51ec3be143ea6bc3ba1075394e559
diff --git a/crates/coset/cargo_embargo.json b/crates/coset/cargo_embargo.json
index 65de91c..fb68599 100644
--- a/crates/coset/cargo_embargo.json
+++ b/crates/coset/cargo_embargo.json
@@ -23,6 +23,11 @@
           "no_std": true
         }
       }
+    },
+    {
+      "features": [],
+      "generate_androidbp": false,
+      "generate_rulesmk": true
     }
   ]
 }
diff --git a/crates/coset/rules.mk b/crates/coset/rules.mk
index a41ac8f..78dd190 100644
--- a/crates/coset/rules.mk
+++ b/crates/coset/rules.mk
@@ -1,18 +1,16 @@
-# This file is generated by cargo2rulesmk.py --run.
-# Do not modify this file as changes will be overridden on upgrade.
+# This file is generated by cargo_embargo.
+# Do not modify this file after the LOCAL_DIR line
+# because the changes will be overridden on upgrade.
+# Content before the first line starting with LOCAL_DIR is preserved.
 
 LOCAL_DIR := $(GET_LOCAL_DIR)
 MODULE := $(LOCAL_DIR)
 MODULE_CRATE_NAME := coset
-MODULE_SRCS := \
-	$(LOCAL_DIR)/src/lib.rs \
-
+MODULE_RUST_CRATE_TYPES := rlib
+MODULE_SRCS := $(LOCAL_DIR)/src/lib.rs
 MODULE_RUST_EDITION := 2018
-MODULE_RUSTFLAGS += \
-	--cfg 'feature="default"' \
-
 MODULE_LIBRARY_DEPS := \
-	external/rust/crates/ciborium \
-	external/rust/crates/ciborium-io \
+	$(call FIND_CRATE,ciborium) \
+	$(call FIND_CRATE,ciborium-io)
 
 include make/library.mk