Disable code_coverage.other for riscv64

code_coverage.policy.other is supposed to install a policy for the
"other" architecture, e.g. arm for arm64.  riscv64 doesn't have an
"other" architecture, disable the module.

Test: builds
Change-Id: Ic42c706dd9c1efe4b0fe9fa7c9823a2a379ba56b

code_coverage/Android.bp

@@ -76,12 +76,8 @@ prebuilt_etc {
             },
         },
         riscv64: {
-            src: "empty_policy/code_coverage.riscv64.policy",
-            product_variables: {
-                native_coverage: {
-                    src: "seccomp_policy/code_coverage.riscv64.policy",
-                },
-            },
+            // riscv64 doesn't have a secondary architecture.
+            enabled: false,
         },
         x86: {
             src: "empty_policy/code_coverage.x86_64.policy",