Documentation: DT: Add entry for FSL Management Complex

* Freescale Management Complex

The Freescale Management Complex (fsl-mc) is a hardware resource

manager that manages specialized hardware objects used in

network-oriented packet processing applications. After the fsl-mc

block is enabled, pools of hardware resources are available, such as

queues, buffer pools, I/O interfaces. These resources are building

blocks that can be used to create functional hardware objects/devices

such as network interfaces, crypto accelerator instances, L2 switches,

etc.

Required properties:

    - compatible

        Value type: <string>

        Definition: Must be "fsl,qoriq-mc".  A Freescale Management Complex

                    compatible with this binding must have Block Revision

                    Registers BRR1 and BRR2 at offset 0x0BF8 and 0x0BFC in

                    the MC control register region.

    - reg

        Value type: <prop-encoded-array>

        Definition: A standard property.  Specifies one or two regions

                    defining the MC's registers:

                       -the first region is the command portal for the

                        this machine and must always be present

                       -the second region is the MC control registers. This

                        region may not be present in some scenarios, such

                        as in the device tree presented to a virtual machine.

Example:

        fsl_mc: fsl-mc@80c000000 {

                compatible = "fsl,qoriq-mc";

                reg = <0x00000008 0x0c000000 0 0x40>,    /* MC portal base */

                      <0x00000000 0x08340000 0 0x40000>; /* MC control reg */

        };