wandboard: Drop revision specific DeviceTree support
The 3.10.53 and 3.14.28 Wandboard kernels handles the revision in a
single DeviceTree file so the boot script needs to respect that.
This should be reworked in the Wandboard kernel to make it to use the
same schema adppted by the Linux mainline and allow an easy change
between them, however, this need be coordinated before we can do this
in the FSL Community fork as well.
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>
