Use platform security domains in keymint/gatekeeper sepolicy

... rather than Cuttlefish sepolicy.

Issue reported by rkir@.

Bug: b/374158137
Test: cvd create
Change-Id: I7522187100e4c8ec94aade5f3cb791087900f7e0
diff --git a/security/keymint/aidl/default/file_contexts b/security/keymint/aidl/default/file_contexts
index dce7e3c..41b02d5 100644
--- a/security/keymint/aidl/default/file_contexts
+++ b/security/keymint/aidl/default/file_contexts
@@ -1,3 +1,3 @@
 (/.*)?                                                           u:object_r:vendor_file:s0
 /etc(/.*)?                                                       u:object_r:vendor_configs_file:s0
-/bin/hw/android\.hardware\.security\.keymint-service\.nonsecure  u:object_r:hal_keymint_rust_exec:s0
+/bin/hw/android\.hardware\.security\.keymint-service\.nonsecure  u:object_r:hal_keymint_default_exec:s0