Revert "fix layer priority shadowing bug"
Revert "fix layer priority shadowing bug"

This patch seems to brake layer priority setting. So it is not the fix
I was looking for. The layer priority from a nested layer is now still
dependend on the layer ordering of bblayers.conf.

This reverts commit af7045233f882a66bc86172851abee5a6bdca29d.

PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec,PHYTEC-Messtechnik-GmbH/meta-phytec