Improve aarch64 filesystem image hygene #1144
Description
The following lines are printed by dmesg when booting on aarch64 with the ubuntu_with_ssh image:
[ 0.865342] fff
[ 0.865346] aaaa 0
[ 0.873568] aaaa 0
[ 0.883017] aaaa 0
[ 0.892489] aaaa 0
[ 0.901964] aaaa 0
[ 0.912685] aaaa 0
[ 0.922161] aaaa 0
[ 0.931688] bbb 0 irq 9
[ 0.941138] cc 0 irq 9 name
[ 0.952661] lll
[ 0.966234] fffi 0
These look like they were somehow added when creating the filesystem image.
Also these ones:
[ 1.845193] tun: Universal TUN/TAP device driver, 1.6
[ 1.879417] probe
[ 1.879447] adada