always pull guest kernel but don't build

[il-steffen]

Always pull linux-guest so we have something to work with. Only leave configure/build to the user workflow.

[Wenzel]

I would propose to conditionaly include build.yml

- name: Clone linux-guest repo
  git:
    repo: "{{ guest_url }}"
    dest: "{{ guest_root }}"
    version: "{{ guest_revision | default(omit) }}"
    depth: "{{ git_clone_depth | default(omit) }}"
    force: yes

- name: Build the TDX guest kernel
  include_tasks: build.yml
  tags:
    - guest-build
    - never