Remove 'kernel_module' variable and adjust code accordingly.
Remove 'kernel_module' variable and adjust code accordingly.

The only place where the check made sense, ie for modprobe, is now
replaced by a check whether the required module is built-in to the
kernel, in which case it isn't needed.
For the rest, well, the checks didn't make sense at all.

beylsp/rpi-installer,beylsp/rpi-installer,yodaaut/raspbian-ua-netinst