Add android16-6.12 microdroid kernel prebuilts to Android.bp

This doesn't switch microdroid to android16-6.12 based kernel just yet.
The switch will be done separately once b/381400679 is fixed.

Bug: 377677758
Test: change RELEASE_AVF_MICRODROID_KERNEL_VERSION to android16_612
Test: atest MicrodroidTests
Change-Id: I3cfa39749527d8adafc370e03b55dd98b154ab39
diff --git a/guest/kernel/Android.bp b/guest/kernel/Android.bp
index d3249f6..cb46e38 100644
--- a/guest/kernel/Android.bp
+++ b/guest/kernel/Android.bp
@@ -31,6 +31,7 @@
     // Below are properties that are conditionally set depending on value of build flags.
     srcs: select(release_flag("RELEASE_AVF_MICRODROID_KERNEL_VERSION"), {
         "android15_66": ["android15-6.6/arm64/kernel-6.6"],
+        "android16_612": ["android16-6.12/arm64/kernel-6.12"],
         default: [],
     }),
 }
@@ -40,6 +41,7 @@
     // Below are properties that are conditionally set depending on value of build flags.
     srcs: select(release_flag("RELEASE_AVF_MICRODROID_KERNEL_VERSION"), {
         "android15_66": ["android15-6.6/x86_64/kernel-6.6"],
+        "android16_612": ["android16-6.12/x86_64/kernel-6.12"],
         default: [],
     }),
 }
@@ -49,6 +51,7 @@
     // Below are properties that are conditionally set depending on value of build flags.
     srcs: select(release_flag("RELEASE_AVF_MICRODROID_KERNEL_VERSION"), {
         "android15_66": ["android15-6.6/arm64/16k/kernel-6.6"],
+        "android16_612": ["android16-6.12/arm64/16k/kernel-6.12"],
         default: [],
     }),
 }