Drop TODO for flag enablement

Flag control for enabling Secretkeeper is done in the device-specific
makefiles, triggering whether they set SECRETKEEPER_ENABLED:=true

Test: none, comment change
Change-Id: I399d1840519864687aca6c53697317d449eed325
diff --git a/trusty/trusty-base.mk b/trusty/trusty-base.mk
index 5aa4392..b21eca6 100644
--- a/trusty/trusty-base.mk
+++ b/trusty/trusty-base.mk
@@ -35,7 +35,6 @@
     LOCAL_KEYMINT_PRODUCT_PACKAGE := android.hardware.security.keymint-service.trusty
 endif
 
-# TODO(b/306364873): move this to be flag-controlled?
 ifeq ($(SECRETKEEPER_ENABLED),true)
     LOCAL_SECRETKEEPER_PRODUCT_PACKAGE := android.hardware.security.secretkeeper.trusty
 else