Make gralloc apex bootstrap

Some early_hal depends on gralloc-mapper.

Bug: 325029533
Test: CF auto boots
Change-Id: I4a89c827c60bf5a44f3667664633c92a3eb2d99f

guest/hals/gralloc/apex_manifest.json

diff --git a/guest/hals/gralloc/apex_manifest.json b/guest/hals/gralloc/apex_manifest.json
index aaa1d88..b49959e 100644
--- a/guest/hals/gralloc/apex_manifest.json
+++ b/guest/hals/gralloc/apex_manifest.json
@@ -1,4 +1,5 @@
 {
     "name": "com.google.cf.gralloc",
-    "version": 1
+    "version": 1,
+    "vendorBootstrap": true
 }
\ No newline at end of file