dt/bindings: Introduce the FSL QorIQ DPAA BMan portal(s)

Portals are memory mapped interfaces to BMan that allow low-latency,
lock-less interaction by software running on processor cores,
accelerators and network interfaces with the BMan

Signed-off-by: Emil Medve <Emilian.Medve@Freescale.com>
Change-Id: I6d245ffc14ba3d0e91d403ac7c3b91b75a9e6a95
Signed-off-by: Scott Wood <scottwood@freescale.com>