Allow default drm hal to access allocator hal

This fixes failing vts drm tests

bug:67675811

Test:vts-tradefed run commandAndExit vts -m VtsHalDrmV1_0Target
Change-Id: I2f7e1c97e8c70fc312ca3c2c901f0a9607b05e83
diff --git a/vendor/hal_drm_default.te b/vendor/hal_drm_default.te
index b79c3b5..0dac075 100644
--- a/vendor/hal_drm_default.te
+++ b/vendor/hal_drm_default.te
@@ -6,3 +6,5 @@
 
 allow hal_drm_default mediacodec:fd use;
 allow hal_drm_default { appdomain -isolated_app }:fd use;
+
+allow hal_drm_default hal_allocator_server:fd use;