Revert "soong: Export bootloader_message_offset to dependencies"

* Fix build, revert when/if this is needed again.

This reverts commit 1b4ecdcb1cbf873cc70ada41faa6693511601720.

Change-Id: I14ec026d8be7297319564340b84ceb164dccfdd5
diff --git a/build/soong/Android.bp b/build/soong/Android.bp
index 7624816..ee9e309 100644
--- a/build/soong/Android.bp
+++ b/build/soong/Android.bp
@@ -296,10 +296,7 @@
     module_type: "cc_defaults",
     config_namespace: "blissGlobalVars",
     value_variables: ["bootloader_message_offset"],
-    properties: [
-        "cflags",
-        "export_cflags",
-    ],
+    properties: ["cflags"],
 }
 
 bootloader_message_offset {
@@ -307,7 +304,6 @@
     soong_config_variables: {
         bootloader_message_offset: {
             cflags: ["-DBOARD_RECOVERY_BLDRMSG_OFFSET=%s"],
-            export_cflags: ["-DBOARD_RECOVERY_BLDRMSG_OFFSET=%s"],
         },
     },
 }