[SOC][RPI][ADD] add Raspberry Pi support to Clea OS core
Add support for Raspberry Pi through these layers:
- meta-raspberrypi: official BSP layer provided by the vendor,
- meta-seco-rpi: SECO layer that integrate the official BSP into Clea OS
CLEAOS-535
Signed-off-by: Alessandro Pecugi alessandro.pecugi@seco.com