powerpc/fsl: Frame Manager Device Tree binding document

The Frame Manager (FMan) combines the Ethernet network interfaces with
packet distribution logic to provide intelligent distribution and
queuing decisions for incoming traffic at line rate.

This binding document describes Freescale's Frame Manager hardware
attributes that are used by the Frame Manager driver for its basic
initialization and configuration.

Signed-off-by: Igal Liberman <Igal.Liberman@freescale.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>