powertop: inherit update-alternatives and use a higher priority than busybox
busybox-1.18.4 installs /bin/powertop and the powertop recipe installs
/usr/bin/powertop. So, in PATH, if /bin appears before /usr/bin, we would
run the version offered by busybox, which has a very limited function (e.g.,
no parameter is accepted) and this causes trouble to eclipse plugin.
We can use update-alternatives for powertop with higher priority to resolve
the issue.
