arm: mx6: cm_fx6: add usb support

Add USB and USB OTG host support for Compulab CM-FX6 CoM.

Cc: Igor Grinberg <grinberg@compulab.co.il>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Tom Rini <trini@ti.com>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>