Mark `ro.kernel` properties as deprecated

emulator migrated to `ro.boot`

Bug: 182291166
Test: presubmit
Signed-off-by: Roman Kiryanov <rkir@google.com>
Change-Id: I9cd443801ff7120ebb628acdc811f0eb339a02c9
diff --git a/private/property_contexts b/private/property_contexts
index dae6939..8872e7e 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -954,6 +954,8 @@
 
 ro.hwui.use_vulkan u:object_r:exported_default_prop:s0 exact bool
 
+# ro.kernel.* properties are emulator specific and deprecated. Do not use.
+# Should be retired once presubmit allows.
 ro.kernel.qemu             u:object_r:exported_default_prop:s0 exact bool
 ro.kernel.qemu.            u:object_r:exported_default_prop:s0
 ro.kernel.android.bootanim u:object_r:exported_default_prop:s0 exact int