Version bump to AP1A.231215.009.X1 [core/build_id.mk]

Change-Id: Iec52627fef8b7d1219ff6b4ce5867004834d2b85
diff --git a/core/build_id.mk b/core/build_id.mk
index d3db436..ff0488d 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,4 +18,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-BUILD_ID=AP1A.231215.009
+BUILD_ID=AP1A.231215.009.X1