Mark selinux_policy_* phony targets with their partition

This is an extension of https://r.android.com/3311944 which marked
selinux_policy_system_ext as system_ext_specific. phony modules do not
have any build actions, but setting the partition tag helps with the
classification heuristic used to autogenerate the soong partition
modules.

Test: Verified that the following files get added to soong-built vendor
partition with this change
  etc/selinux/plat_pub_versioned.cil
  etc/selinux/plat_sepolicy_vers.txt
  etc/selinux/selinux_denial_metadata
  etc/selinux/vendor_file_contexts
  etc/selinux/vendor_hwservice_contexts
  etc/selinux/vendor_keystore2_key_contexts
  etc/selinux/vendor_mac_permissions.xml
  etc/selinux/vendor_property_contexts
  etc/selinux/vendor_seapp_contexts
  etc/selinux/vendor_sepolicy.cil
  etc/selinux/vendor_service_contexts
  etc/selinux/vndservice_contexts

Bug: 374371755
Change-Id: I27934c3796f999546aacbf1e1e88a2101b4e5975
diff --git a/Android.bp b/Android.bp
index 9905e73..d1ef861 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1040,6 +1040,7 @@
             "product_202404.cil",
         ],
     }),
+    product_specific: true,
 }
 
 phony {
@@ -1086,6 +1087,7 @@
         ],
         default: [],
     }),
+    vendor: true,
 }
 
 phony {