SF: Add a readonly feature flag for display config error HAL changes

Bug: 374184110
Test: adb shell dumpsys SurfaceFlinger | grep display_config_error_hal
-- Verify that the flag shows up
Flag: com.android.graphics.surfaceflinger.flags.display_config_error_hal

Change-Id: I78af63115914c8ae53dbb04f6d86f601e502ec8f
Signed-off-by: Manasi Navare <navaremanasi@google.com>
diff --git a/services/surfaceflinger/surfaceflinger_flags_new.aconfig b/services/surfaceflinger/surfaceflinger_flags_new.aconfig
index e40be51..245bc2a 100644
--- a/services/surfaceflinger/surfaceflinger_flags_new.aconfig
+++ b/services/surfaceflinger/surfaceflinger_flags_new.aconfig
@@ -74,6 +74,14 @@
 } # detached_mirror
 
 flag {
+  name: "display_config_error_hal"
+  namespace: "core_graphics"
+  description: "Report HAL display configuration errors like modeset failure or link training failure"
+  bug: "374184110"
+  is_fixed_read_only: true
+} # display_config_error_hal
+
+flag {
   name: "filter_frames_before_trace_starts"
   namespace: "core_graphics"
   description: "Do not trace FrameTimeline events for frames started before the trace started"