Microdroid: Add support for android15-6.6 GKI as guest kernel

Bug: 325991735
Test: build & install virt APEX with android15-6.6 GKI
Test: AVF presubmit tests
Change-Id: I16b5b4e0927cbddd000d17724319bcecd5ab6640
diff --git a/apex/Android.bp b/apex/Android.bp
index 17b1f9e..da17040 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -36,6 +36,7 @@
     name: "avf_microdroid_guest_gki_version",
     values: [
         "android14_61_pkvm_experimental",
+        "android15_66",
     ],
 }
 
@@ -175,6 +176,14 @@
                     "microdroid_gki-android14-6.1-pkvm_experimental.json",
                 ],
             },
+            android15_66: {
+                prebuilts: [
+                    "microdroid_gki-android15-6.6_initrd_debuggable",
+                    "microdroid_gki-android15-6.6_initrd_normal",
+                    "microdroid_gki-android15-6.6_kernel",
+                    "microdroid_gki-android15-6.6.json",
+                ],
+            },
         },
         release_avf_enable_device_assignment: {
             prebuilts: [