Pixel Common: system_dlkm: avb hashtree footer

Add avb hashtree footer args for the system_dlkm
partition required for the T launch devices.

Bug: 222334390
Test: TH, manual build, Code testing gs101 & R6
Signed-off-by: Ramji Jiyani <ramjiyani@google.com>
Change-Id: I7a28ccfa2acad2e20c35a8a68edbffcca068678e