mx6: Add initial support for the Hummingboard solo

SolidRun has designed the Hummingboard board based on mx6q/dl/solo.

Add the initial support for the mx6 solo variant.

More information about this hardware can be found at:
http://imx.solid-run.com/wiki/index.php?title=Carrier-One_Hardware



(Carrier-One was the previous name of Hummingboard).

Based on the work from Jon Nettleton <jon.nettleton@gmail.com>.

Signed-off-by: Jon Nettleton <jon.nettleton@gmail.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>