imagebuilder: fix main entry makefile

Remove a syntax error from ImageBuider Makefile

Acked-by: Paul Spooren <[email protected]>
Signed-off-by: Paulo Machado <[email protected]>

target/imagebuilder/files/Makefile

@@ -138,7 +138,7 @@ package_index: FORCE
 	(cd $(PACKAGE_DIR); $(SCRIPT_DIR)/ipkg-make-index.sh . > Packages && \
 		gzip -9nc Packages > Packages.gz; \
 		$(if $(CONFIG_SIGNATURE_CHECK), \
-			$(STAGING_DIR_HOST)/bin/usign -S -m Packages -s $(BUILD_KEY)); \
+			$(STAGING_DIR_HOST)/bin/usign -S -m Packages -s $(BUILD_KEY)) \
 	) >/dev/null 2>/dev/null
 	$(OPKG) update >&2 || true