Remove system_linker_config module

The linker.config.pb on the system image has some system-specific
build steps. The system_linker_config module was just one of the
steps, but the rest of the steps depend on installed files, which
are only known to the filesystem modules, so they happen there.
Move this first initial step to the filesystem level as well for
consistency.

Bug: 384091387
Test: Diff'd out/target/product/vsoc_x86_64/system/etc/linker.config.pb before and after this cl
Change-Id: Ia3a613eee730778a6bd3aeb196c53cee0eb576bf
diff --git a/rootdir/Android.bp b/rootdir/Android.bp
index d3db2ff..121652c 100644
--- a/rootdir/Android.bp
+++ b/rootdir/Android.bp
@@ -61,13 +61,6 @@
     srcs: ["etc/linker.config.json"],
 }
 
-// TODO(b/147210213) Generate list of libraries during build and fill in at build time
-linker_config {
-    name: "system_linker_config",
-    src: ":system_linker_config_json_file",
-    installable: false,
-}
-
 // TODO(b/185211376) Scope the native APIs that microdroid will provide to the app payload
 prebuilt_etc {
     name: "public.libraries.android.txt",