Remove obsolete visibility entries from libc_headers

cc_objects get libc headers by default now unless they opt out through
system_shared_libs: [] or default_shared_libs: [], so they no longer
need explicit visibility.

Fixes: b/153662223
Test: m nothing
Change-Id: Ib61a597cbfee4616a632abdfbf4b4f108d35c2b6
diff --git a/libc/Android.bp b/libc/Android.bp
index d24e387..aa5d435 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -1938,11 +1938,6 @@
         "//external/scudo",
         "//system/core/property_service/libpropertyinfoparser",
         "//system/extras/toolchain-extras",
-        // TODO(b/153662223): Clean up these users that needed visibility when
-        // the implicit addition of system Bionic paths was removed.
-        "//art/tools/cpp-define-generator",
-        "//external/boringssl",
-        "//external/minijail",
     ],
 
     stl: "none",