ebtables: add from OE-Classic, update and tidy up

* Update to 2.0.10-4
* Handle hardcoded paths in initscript
* Add LIC_FILES_CHKSUM
* Set SUMMARY (which sets DESCRIPTION)
* Drop PRIORITY
* Minor formatting/ordering tweaks

Based on a patch by Vladimir Redzhepoff <vladimir.redzhepoff@promwad.com>

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>