Revert "Revert "Move ramdisk to the new init_boot partition""

This reverts commit 3c76abb8ea0c3c95e53a38c13c9e29791e0f10ae.

Reason for revert: Presubmits should now pass with fixed u-boot prebuilts

Change-Id: I5f60c10640cd19ee2ed4b874a077c1596a53e612
diff --git a/apex/Android.bp b/apex/Android.bp
index f1eeed9..25cd480 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -5,6 +5,7 @@
 microdroid_filesystem_images = [
     "microdroid_super",
     "microdroid_boot-5.10",
+    "microdroid_init_boot",
     "microdroid_vendor_boot-5.10",
     "microdroid_vbmeta",
     "microdroid_vbmeta_bootconfig",