package/arp-scan: bump version to 1.9.6

Removed patch which was applied upstream:
https://github.com/royhills/arp-scan/commit/cbeda6a9c5e154fd5e5d56e3e6e6bdc5ddd2b088



We still need autoreconf however due to using source code retrieved by
the github helper.

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>