Freeze kernel configs for r.

Bug: 151966896
Test: builds
Change-Id: Iefad197353738410dc066531a6e14e3df96449d4
diff --git a/compatibility_matrices/Android.bp b/compatibility_matrices/Android.bp
index 7883dd9..33157a6 100644
--- a/compatibility_matrices/Android.bp
+++ b/compatibility_matrices/Android.bp
@@ -83,8 +83,8 @@
         "compatibility_matrix.current.xml",
     ],
     kernel_configs: [
-        "kernel_config_current_4.14",
-        "kernel_config_current_4.19",
-        "kernel_config_current_5.4",
+        "kernel_config_r_4.14",
+        "kernel_config_r_4.19",
+        "kernel_config_r_5.4",
     ]
 }