Add support for Freescale's mx35pdk board.

The patch adds suupport for the Freescale's mx35pdk board
(known as well as mx35_3stack).

The board boots from the NOR flash. Following devices
are supported:
 - two ethernet devices (FEC and SMC911x on debug board)
 - I2C
 - PMIC (MC13892) via I2C interface
 - UART
 - NOR flash (64MB)
 - NAND flash (2GB)
 - basic access to mc9sdz60 registers via I2C interface

Signed-off-by: Stefano Babic <sbabic@denx.de>