Add basic support for CompuLab cm-t335 module based on AM335X SoC.

CM-T335 is a tiny computer-on-module (CoM) / system-on-module (SoM)
The module is built around the Texas Instruments Sitara AM3352/4
system-on-chip.

The CPU is supplemented with up-to 512MB DDR3 and up-to 1GB of on-board
NAND storage, WiFi connected to SPI, Bluetooth, Analog audio, Gigabit
Ethernet, CAN bus.

Current patch adds support:
UART0 and GPIO LED

Detailed description can be found at the module site:
http://www.compulab.co.il/products/computer-on-modules/cm-t335/Signed-off-by: NIlya Ledvich <ilya@compulab.co.il>
[uri.mashiach@compulab.co.il: the default RAM amount reduced to
128MB to support also the minimal module configuration]
Signed-off-by: NUri Mashiach <uri.mashiach@compulab.co.il>
Acked-by: NIgor Grinberg <grinberg@compulab.co.il>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NTony Lindgren <tony@atomide.com>