Add emulator support for T4240. Emulator has limited peripherals and
interfaces. Difference between emulator and T4240QDS includes:
ECC for DDR is disabled due the procedure to load images
No board FPGA (QIXIS)
NOR flash has 32-bit port for higher loading speed
IFC and I2C timing don't really matter, so set them fast
No ethernet
Signed-off-by: York Sun <yorksun@freescale.com>
