move machine confs to bsp layers

- autoload-filesystems.inc and openpli.inc contained just one line
  so for now just merge them in to the machine confs for those who
  need it.

- As the layers a conf directory with machine defs, append to BBPATH
Merge branch 'master' of git://git.code.sf.net/p/openpli/openpli-oe-core