Remove unused no_vendor_variant_vndk_check target

This was missed when we moved from a single target for checking all
VNDK libraries to using timestamp files for checking individual VNDK
libraries.

Test: Build success.
Change-Id: I3be19f6755b24fff2446449a9dbc84db9a20ea41
diff --git a/core/main.mk b/core/main.mk
index cb44106..ec1effd 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -444,10 +444,6 @@
 subdir_makefiles_total := $(words init post finish)
 endif
 
-droid_targets: no_vendor_variant_vndk_check
-.PHONY: no_vendor_variant_vndk_check
-no_vendor_variant_vndk_check:
-
 $(info [$(call inc_and_print,subdir_makefiles_inc)/$(subdir_makefiles_total)] finishing build rules ...)
 
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