core/config.mk: Add PLATFORM_SEPOLICY_COMPAT_VERSIONS

This is a list of sepolicy versions that the framework supports.

Test: build framework compatibility matrix
Test: boots

Bug: 67920434
Change-Id: I82365742172b653eadb7b5315398e06cace4e000
diff --git a/core/config.mk b/core/config.mk
index 47e60a8..a32e9f2 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -872,6 +872,11 @@
 sepolicy_major_vers :=
 sepolicy_minor_vers :=
 
+# A list of SEPolicy versions, besides PLATFORM_SEPOLICY_VERSION, that the framework supports.
+PLATFORM_SEPOLICY_COMPAT_VERSIONS := \
+    26.0 \
+    27.0
+
 # ###############################################################
 # Set up final options.
 # ###############################################################