parallella-common: Add machine override, setup image types
parallella-common: Add machine override, setup image types

Add a machine override 'parallella-common' for use to setup variables
for parallella machines in common.

Setup the image types to include cpio.gz.u-boot.

Signed-off-by: Nathan Rossi <2e8aa918660411855c6d44d5bb2da677aa033255@nathanrossi.com>

nathanrossi/meta-parallella