test-baremetal: fix missing setting x0 return value
Examples were just returning on ret without setting x0, which led to
failures... those were not noticed because of how broken the testing system
was ;-)
Motivation: userland is getting several new subdirectories, it would be
too insane to just dump all of that in the guest root filesystem.
To alleviate the cd pain, .profile puts user inside /lkmc by default.
