Add option to invoke QEMU with a PVM template

Add -T command line option to aarch64/ which invokes QEMU
with a given file as a PVM template.

It will automatically determine the address at which the file will be
placed in memory. This is based on the fixed QEMU memory layout:
    kernel | initrd | dtb | template

It will run QEMU first to dump its DTB and then overlay it with a node
specifying the address and size of the template before running QEMU

Bug: 171309087
Test: with a script:
      hexdump -C /proc/device-tree/pkvm_template@*/reg
Change-Id: I82dd50f407dc45f9dc615c702e25841b607bbb61
1 file changed
tree: 572433c51d9a580a0b42d3ed255f95956452a572
  1. Makefile
  2. aarch64/
  4. kvm-unit-tests/