core-image-pelux: append swupdate only for rpi
core-image-pelux: append swupdate only for rpi

Instead of including swupdate in all images and then removing when needed
only append where we want it.

Signed-off-by: Therese Nordqvist <2d0f96d8a993fd0656366c2e00899126ff42525a@pelagicore.com>

Pelagicore/meta-pelux,GordanM/meta-pelux,Pelagicore/meta-pelux,GordanM/meta-pelux,Pelagicore/meta-pelux