[POWERPC] Fix the node index confusion for SOC

    1) Defining child nodes of an SOC

    2) Representing devices without a current OF specification

      a) MDIO IO device

      c) PHY nodes

      b) Gianfar-compatible ethernet nodes

      c) PHY nodes

      d) Interrupt controllers

      e) I2C

      f) Freescale SOC USB controllers

      g) Freescale SOC SEC Security Engines

      h) Board Control and Status (BCSR)

      i) Freescale QUICC Engine module (QE)

      g) Flash chip nodes

      j) Flash chip nodes

      k) Global Utilities Block

  VII - Specifying interrupt information for devices