mx6: Add support for Phytec pfla02 (NAND)

Add support for Phytec pfla02, equipped with NAND.

CPU:   Freescale i.MX6Q rev1.5 996 MHz (running at 792 MHz)
CPU:   Automotive temperature grade (-40C to 125C) at 31C
Reset cause: POR
I2C:   ready
DRAM:  1 GiB
NAND:  2048 MiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
SF: Detected n25q128 with page size 256 Bytes, erase size 64 KiB, total
16 MiB
In:    serial
Out:   serial
Err:   serial
Net:   FEC [PRIME]
Hit any key to stop autoboot:  0

Signed-off-by: Stefano Babic <sbabic@denx.de>
CC: Stefan Christ <s.christ@phytec.de>
CC: Stefan Müller-Klieser <S.Mueller-Klieser@phytec.de>
CC: Christian Hemp <C.Hemp@phytec.de>