[STRUCTURE] Make the layer dependent to meta-seco-clea-os

The original architecture was that meta-seco-bsp and meta-seco-clea-os would be the core of Clea OS and would have equal weight in the layer hierarchy. Now meta-seco-bsp loses relevance and becomes the layer that helps make the hardware support layer homogeneous (among the various silicon vendors), providing a common interface upward. Consequently, meta-seco-bsp becomes dependent on meta-seco-clea-os, and part of the generic code (recipes and classes) is moved from meta-seco-bsp to meta-seco-clea-os.

Signed-off-by: Davide Cardillo davide.cardillo@seco.com