kvmtool: Modify remote to use Jean's source

We want to use virtio-iommu implementation from Jean Philippe's
tree for kvmtool. The branch is available at:
https://jpbrucker.net/git/kvmtool/log/?h=virtio-iommu/devel



Update the remote refs and hash to start using this tree.

Signed-off-by: Vivek Gautam <vivek.gautam@arm.com>
Change-Id: Ie53d170a9d24d462bbddba2a6c8ae697f2721ebf