powerpc/corenet: add support for the kmcent2 board

This board is built around Freescale's T1040 SoC.

The peripherals used by this design are:
- DDR3 RAM with SPD support
- parallel NOR Flash as boot medium
- 1 PCIe bus (PCIe1 x1)
- 3 FMAN Ethernet devices (FMAN1 DTSEC1/2/5)
- 4 IFC bus devices:
  - NOR flash
  - NAND flash
  - QRIO reset/power mgmt CPLD
  - BFTIC chassis management CPLD
- 2 I2C buses
- 1 SPI bus
- HDLC bus with the QE's UCC1
- last but not least, the mandatory serial port

The board can be used with the corenet32_smp_defconfig.

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Signed-off-by: Scott Wood <oss@buserror.net>