Fix AVA+R52 execution steps

This follows an OoB test.

An extra package is needed for X forwarding to work on AVA.

Disabling multicast on the Primary Compute prevents the map from loading
correctly when launching the Autoware demo on AVA.

Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
Change-Id: Id27a02058ba30837ab589b9182510576ff274499