Add missing target from makefile

The target was missing in the mk file, causing "commands commence before
first target" error.

Test: TH
Change-Id: I0ec4f636daf1171e81bf9c7c764b15e07a25fc80
diff --git a/core/tasks/vendor_snapshot.mk b/core/tasks/vendor_snapshot.mk
index d1849ab..3623235 100644
--- a/core/tasks/vendor_snapshot.mk
+++ b/core/tasks/vendor_snapshot.mk
@@ -95,6 +95,7 @@
 
 .PHONY: vendor-hwasan-snapshot
 vendor-hwasan-snapshot: PRIVATE_MAKEFILE := $(current_makefile)
+vendor-hwasan-snapshot:
 	$(call echo-error,$(PRIVATE_MAKEFILE),\
 		"CANNOT generate Vendor HWASAN snapshot. BOARD_VNDK_VERSION must be set to 'current'.")
 	exit 1