Convert ramdisk_node_list to Android.bp

`ramdisk_node_list` is a hardcoded dependency in
`build/make/core/Makefile`, but it only serves as an input for
generating `ramdisk.img` and isn't installed on the device.

Therefore, we can directly use a `filegroup` and set
`export_to_make_var` for use in build/make/core/Makefile.

In addition, since there are no `Android.mk` files in the
subdirectories of `system/core/rootdir/`,
`include (callall−makefiles−under,(LOCAL_PATH))` can also be
deleted.

Bug: 359423289
Test: m -j $(PRODUCT_OUT)/ramdisk.img
Change-Id: Ia2bf636bfd7917bf7044d9726b4b52932bb161c8
diff --git a/rootdir/Android.bp b/rootdir/Android.bp
index 1e7b48b..5f0a2c3 100644
--- a/rootdir/Android.bp
+++ b/rootdir/Android.bp
@@ -189,3 +189,9 @@
         (default, default): [],
     }),
 }
+
+filegroup {
+    name: "ramdisk_node_list",
+    srcs: ["ramdisk_node_list"],
+    export_to_make_var: "RAMDISK_NODE_LIST",
+}
diff --git a/rootdir/Android.mk b/rootdir/Android.mk
index e743743..f866e9b 100644
--- a/rootdir/Android.mk
+++ b/rootdir/Android.mk
@@ -151,17 +151,3 @@
 $(eval $(call copy-one-file,$(init.environ.rc-soong),$(LOCAL_BUILT_MODULE)))
 init.environ.rc-soong :=
 
-#######################################
-# ramdisk_node_list
-include $(CLEAR_VARS)
-
-LOCAL_MODULE := ramdisk_node_list
-LOCAL_MODULE_CLASS := ETC
-LOCAL_SRC_FILES := $(LOCAL_MODULE)
-LOCAL_MODULE_PATH := $(PRODUCT_OUT)
-
-LOCAL_LICENSE_KINDS := SPDX-license-identifier-Apache-2.0
-LOCAL_LICENSE_CONDITIONS := notice
-include $(BUILD_PREBUILT)
-
-include $(call all-makefiles-under,$(LOCAL_PATH))