fix Makefile chmod (644)
replace MD5SUM with HASH
add PKG_MIRROR_HASH when PKG_SOURCE_PROTO:=git

(PKG_SOURCE_PROTO:=svn tarballs are not reproducible for now)

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

Update liboping/oping/noping to upstream release 1.9.0
Also introduce new location of downloads and correct
the licence to LGPL-2.1+ (as seen in liboping's README)

Signed-off-by: Paul Wassi <p.wassi@gmx.at>

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

Signed-off-by: Jo-Philipp Wich <jow@openwrt.org>