arm, imx6: add aristainetos board

CPU:   Freescale i.MX6DL rev1.1 at 792 MHz
Board: aristaitenos
I2C:   ready
DRAM:  1 GiB
NAND:  512 MiB
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
SF: Detected N25Q128 with page size 256 Bytes, erase size 64 KiB, total 16 MiB
Display: lb07wv8 (800x480)

- UART5 is console
- MMC 0 and 1
- USB 0 and 1
- boot from mmc0 and spi nor flash
- Splash screen support

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Stefano Babic <sbabic@denx.de>