uboot-imx

arm: dts: Add u-boot specific compatibles

Separate out u-boot specific compatibles from dts files.
This will help in syncing dts files in future.
Also these will get deleted eventually once respective drivers
are capable of handling Linux dts files.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>