virt-aa-helper: allow common riscv64 loader paths
virt-aa-helper: allow common riscv64 loader paths

Riscv64 usually uses u-boot as external -kernel and a loader from
the open implementation of RISC-V SBI. The paths for those binaries
as packaged in Debian and Ubuntu are in paths which are usually
forbidden to be added by the user under /usr/lib...

People used to start riscv64 guests only manually via qemu cmdline,
but trying to encapsulate that via libvirt now causes failures when
starting the guest due to the apparmor isolation not allowing that:
   virt-aa-helper: error: skipped restricted file
   virt-aa-helper: error: invalid VM definition

Explicitly allow the sub-paths used by u-boot-qemu and opensbi
under /usr/lib/ as readonly rules.

Fixes: https://launchpad.net/bugs/1990499

Signed-off-by: Christian Ehrhardt <48da28e2c2cd455d60e19b14c46925e20a3c5d5b@canonical.com>
Reviewed-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

jfehlig/libvirt,zippy2/libvirt,olafhering/libvirt,jfehlig/libvirt,libvirt/libvirt,olafhering/libvirt,libvirt/libvirt,libvirt/libvirt,zippy2/libvirt,jfehlig/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,zippy2/libvirt,jfehlig/libvirt,olafhering/libvirt