Rather than using echo to return the firmware package name, call a
new function (addpkg) which will also deal with (i) no leading space
and (ii) remove duplicates (as some devices have dual-wifi-cards).
In addition we won't have a line break when having multiple packages.
While here also do not call pkg(8) anymore if there is no package to
install and actually use the variable to install all and not just the
last found package.
I would maybe call the hint cppc_notify with the sense being that "1" enables it and "0" disables notifications (we try to avoid "negative" hints/tunables). You would then just want to set the default value to 1 and change the last test to cppcval != 0. I would also perhaps rename cppcval to cppc_notify as well.