dhcp: update 4.4.1

dhcp: update 4.4.1

include several CVE fixes.
CVE: CVE-2018-5733
CVE: CVE-2018-5732

LIC_CHKSUM_FILE updated to SPFX format

https://kb.isc.org/article/AA-01571

remove several patches now included in update.
Shared libarary support is now enabled in configure+lt, use it
and revert to autotools-brokensep
Refresh patches

Aligns support with bind 9.11.x

Add libxml2 support to configure.ac+lt

Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>