partially revert "build: remove check for nonexistant CONFIG_TAR_VERBOSITY variable and move TAR_OPTIONS to unpack.mk"

This complicates the evaluation order for some packages

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@40006 3c298f89-4303-0410-b956-a3cf2f4a3e73